HomeMy WebLinkAboutCDP 16-09; Tabata Ranch Steven & Carey SFR; PALEONTOLOGICAL MONITORING; 2016-02-26' _ _!
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PALEONTOLOGICAL MONITORING REPORT,
TABATA RANCH PROJECT, CARLSBAD,
SAN DIEGO COUNTY, CALIFORNIA
(City of Carlsbad Project No. CT 06-15)
Prepared for:
Tabata Ranch Trust
c/o Rancho Coastal Engineering & Surveying, Inc.
310 Via Vera Cruz #205
San Marcos, California 92078
Prepared by:
George L. Kennedy, Ph.D., Senior Paleontologist
Todd A. Wirths, California Professional Geologist No. 7588
N. Scott Rugh, Adjunct Paleontologist
Brian F. Smith and Associates, Inc.
Consultants in Archaeology, History, Paleontology, and Biology
14010 Poway Road, Suite A, Poway, California 92064
www.bfsa-ca.com
26 February 2016 APR 2 5
PALEONTOLOGICAL MONITORING REPORT,
TABATA RANCH PROJECT, CARLSBAD,
SAN DIEGO COUNTY, CALIFORNIA
(City of Carlsbad Project No. CT 06-15)
Prepared for:
Tahata Ranch Trust
c/o Rancho Coastal Engineering & Surveying, Inc.
310 Via Vera Cruz #205
San Marcos, California 92078
Prepared by:
George L. Kennedy, Ph.D., Senior Paleontologist
Todd A. Wirths, California Professional Geologist No. 7588
N. Scott Rugh, Adjunct Paleontologist
Brian F. Smith and Associates, Inc.
Consultants in Archaeology, History, Paleontology, and Biology
14010 Poway Road, Suite A, Poway, California 92064
www.bfsa-ca.com
26 February 2016
'~
Paleontological Monitoring Report, Tabata Ranch Project
Table of Contents
Section 1.0 Introduction ................................................................................................ 1.0-1
Section 2.0 Background and Previous Work ................................................................ 2.0-1
Section 3.0 Monitoring and Results .............................................................................. 3.0-1
Section 4.0 Summary .................................................................................................... 4.0-1
Section 5.0 References Cited ........................................................................................ 5.0-1
Section 6.0 Appendix (museum letter of collections receipt) ....................................... 6.0-1
Figures
Figure 1.0-1 General location map ................................................................................. 1.0-3
Figure 1.0-2 Project location map, 1:24,000-scale topographic base ............................. 1.0-4
Figure 2.0-1 Geologic map ............................................................................................. 2.0-3
Figure 3.0-1 Stratigraphic column .................................................................................. 3.0-2
Figure 3.0-2 Fossil locality map ..................................................................................... 3.0-6
Table 3.0-1 List of Eocene fossils from the Tabata Ranch project site ......................... 3.0-9
BFSA
LACMIP
SDNHM
SDSNH
SDSU
Institutional Abbreviations
Brian F. Smith and Associates, Inc., Poway
Invertebrate Paleontology Section, Natural History Museum of Los Angeles
County, Los Angeles
San Diego Natural History Museum, San Diego
Department of Paleontology, San Diego Society of Natural History, San Diego
Department of Geological Sciences, San Diego State University, San Diego
Paleontological Monitoring Report, Tabata Ranch Project
1.0 INTRODUCTION
The California Environmental Quality Act (CEQA) requires local governmental agencies
to consider potential impacts to paleontological resources and to implement mitigation measures
to protect those resources if they are likely to be lost or otherwise adversely affected by
construction-related activities. Pursuant to CEQA regulations for excavation and/or construction
related activities, the City of Carlsbad Planning Department required that a Mitigation
Monitoring and Reporting Program (MMRP; Project No. CT 06-15) be implemented because the
planned construction activity would occur in areas that have been judged to be paleontologically
sensitive based on the distribution of known fossil localities and potentially fossil-bearing
sedimentary formations (cf Demere and Walsh, 1993; Stephenson eta!., 2009).
This report deals with paleontological mitigation efforts conducted by BFSA in response
to the City of Carlsbad Planning Department's environmental mitigation requirements (MMRP),
as specified for the Tabata Ranch housing subdivision project (Project No. CT 06-15). The
project site comprises three original parcels (Assessor's Parcel Numbers 214-630-20, 214-631-
20, and 214-631-21) and is divided into five residential lots and building pads. Access to the
western three lots is off of Strawberry Place (new), whereas access to the eastern two lots is off
of the cul-de-sac at the end of Lemon Leaf Drive in Carlsbad, northern San Diego County,
California (Figures 1.0-1 and 1.0-2). Earth-moving activities involved approximately 19,600
cubic yards of cut and 2,400 cubic yards of fill during the grading and excavation processes on
the site. Elevations across the site range from about 249 feet above mean sea level (AMSL) on
the west end of Strawberry Place (at Lonicera Street) to about 308 feet AMSL in the northeast
corner of the development (near the end of Lemon Leaf Drive). On the U.S. Geological Survey,
7.5-minute, 1 :24,000-scale Encinitas, California topographic quadrangle map (1968,
photorevised 1975), the subject property is located in the very northeast corner of Section 28,
Township 12 South, Range 4 West, San Bernardino Base and Meridian (Figure 1.0-2).
On the basis of a review of relevant published literature, unpublished environmental and
geotechnical reports, and knowledge of the local geology and of southern California museum and
university fossil collections and locality records of the Department of Paleontology at the
SDNHM, the Department of Geological Sciences at SDSU, and the LACMIP in Los Angeles, it
was determined that marine invertebrate fossils should be expected to be found in the middle
Eocene(~ 50 to~ 40 million year old) sediments of the Santiago Formation exposed across the
site, as well as from the overlying middle to lower Pleistocene Lindavista Formation. Nearby
projects that resulted in the recovery of Eocene and/or Pleistocene fossils include those of Shiller
and Kennedy (2003), Browne and Demere (2006), and Kennedy and Shiller (2009). Demere and
Walsh (1993) and Stephenson et a!. (2009) have assigned a "high paleontological resource
sensitivity" to the Santiago Formation and a "moderate paleontological resource sensitivity" to
the Lindavista Formation in this area, supporting the requirement for paleontological monitoring
for the Tabata Ranch project.
Paleontological monitoring of earth-moving and trenching activities for the project
occurred intermittently, as needed, between March 31, 2014 and July 15, 2014. Monitoring
mainly consisted of active observations of all earth-moving activities, including trenching for
utilities. In addition, all spoil piles generated by these activities were also carefully examined, as
1.0-1
Paleontological Monitoring Report, Tabata Ranch Project
well as freshly cut slopes and sidewall exposures within the utility trenches. Ten paleontological
salvage collections were made by paleontological monitors Claire M. Allen, Jeffrey K. Henry,
Mary K. Klinger, James S. Shrieve, and Todd A. Wirths in June and July of 2014. The
paleontological monitoring program was under the direction and supervision of Dr. G. L.
Kennedy, Senior Paleontologist with BFSA, and T. A. Wirths, California Professional Geologist
No. 7588. Dr. Kennedy was responsible for overseeing the laboratory preparation and curation
of the fossil remains. Identification of the discovered fossils was done by N. S. Rugh. Fossils
have been deposited in the SDNHM in Balboa Park, San Diego, where they are to receive long-
term archival care and conservation. The archived collections bear SDSNH locality numbers
6816 through 6819 and SDSNH specimen/species lot numbers 141400 through 141467.
1.0-2
Figure 1.0-1
General Location Map
The Tabata Ranch Project
DeLorme (1 :250,000)
1.0-3
Figure 1.0-2
Project Location Map
The Tabata Ranch Project
USGS Encinitas Quadrangle (7.5-minute series)
1.0-4
Paleontological Monitoring Report, Tabata Ranch Project
2.0 BACKGROUND AND PREVIOUS WORK
Geomorphically, the project area is located in the previously relatively flat, but
subsequently highly dissected, region previously referred to as the composite Linda Vista terrace,
the sediments of which were assigned to the Linda vista Formation. The multiple marine terraces
in this terrace complex have cut across and truncated the older underlying middle Eocene
sediments. The resulting contact is often found to have been bored by bivalve mollusks when
this abraded surface was the sea floor in Lindavista time. The closest examples of these
boreholes were recovered during monitoring of the Morning Ridge project about one mile east of
the current project (LACMIP loc. 17382; Shiller and Kennedy, 2003). The lower Tertiary (or
Paleogene) estuarine and marine sedimentary rocks in this part of San Diego County are
currently assigned to the middle Eocene (~ 50 to ~ 40 million year old) Santiago Formation
(Figure 2.0-1, after Kennedy and Tan, 2005, sheet 1; see also Tan and Kennedy, 1996, pl. 2),
although in the past they have been assigned to other named formations (cf Givens and
Kennedy, 1976) that are known to crop out farther to the south.
Fossiliferous middle Eocene sedimentary rocks in the Carlsbad area have been known for
many years. In more recent years, they have been assigned to the Santiago Formation, a
formational name originally proposed for similar sedimentary rocks in southern Orange County.
Lagoonal, estuarine to fully marine facies of the formation are typically assigned to informal
"member B" and assigned an age of~ 46 to~ 42 million years, correlative with the early part of
the Uintan North American Land Mammal Age (Demere and Walsh, 1993). Because of the
sometimes exquisite preservation of fossils from the Santiago Formation, local exposures of the
formation have provided important contributions to our knowledge of Eocene marine and
estuarine life in southern California (e.g., Givens and Kennedy, 1976; Squires and Saul, 2002),
including the descriptions of a number of previously unknown and unnamed new species.
The literature search and an examination of museum and university fossil collections
and/or locality records ofthe SDSNH, SDSU, and LACMIP (which also includes the collections
of the University of California at Los Angeles, the University of Southern California, and the
California Institute of Technology), revealed a number of nearby fossil localities assigned to both
the Pleistocene Linda vista Formation and the middle Eocene Santiago Formation sediments,
particularly to the north, west of El Camino Real, and to the east (SDSNH collection records).
North of the project area, Browne and Demere (2006) document one well preserved marine
invertebrate fauna from the Neighborhood 1.17 project site (SDSNH loc. 5744) that produced at
least 18 species of bivalve mollusks, 21 or more species of gastropods, one scaphopod (tusk
shell), decapod crustaceans, and cartilaginous and bony fish remains. The best preserved fossils
from the Santiago Formation, including several new species, were originally discovered by San
Diego State College students in the 1960s, when the State Route 78 freeway was being
constructed through nearby Vista (e.g., see Givens and Kennedy, 1976). The highway exposures
were subsequently recollected by a number of geologists and paleontologists, including SDNHM
staff members, when State Route 78 was subsequently widened ( cf museum collection records).
It is always hoped that any newly discovered fossiliferous exposures will be as exquisitely
preserved as those from nearby Vista.
2.0-1
Figure 2.0-1
Geologic Map
The Tabata Ranch Project
Geology after Kennedy and Tan (2005)
2.0-2
0 1000 2000 ft
Paleontological Monitoring Report, Tabata Ranch Project
3.0 MONITORING AND RESULTS
Paleontological monitoring of grading, excavation, and utility trenching activities at the
project development site occurred intermittently, as needed, between March 31, 2014 and July
15, 2014. Monitoring activities involved close observations of all grading, cutting, excavation,
and trenching activities, as well as examinations of all fresh cuts and any accumulated spoil and
temporary stock piles generated by these activities. Abundant Eocene fossils were collected
from two general areas in the Santiago Formation and represent three stratigraphic levels, as
shown on the stratigraphic column for the project (Figure 3.0-1 ). The fossil localities have been
assigned SDSNH locality numbers 6816 through 6819. Fossils identified at these localities are
listed in Table 3.0-1. No fossils were observed in the sediments of the Pleistocene Lindavista
Formation.
3.1 Stratigraphy: Based on the fieldwork ofT. A. Wirths and others, the sedimentary
units exposed across the Tabata Ranch project site include lower to middle Pleistocene paralic
sediments of the overlying Lindavista Formation, which unconformably overlie middle Eocene
clayey siltstones and silty very fine-grained sandstones assigned to the Santiago Formation
(Figure 3.0-1). The Santiago Formation sediments observed can be subdivided into three
lithologic units: an upper clayey siltstone, a middle silty very fine-grained sandstone unit, and a
lower clayey siltstone unit. These units are described in telegraphic style in more detail below.
•
•
•
•
Lindavista Formation. Paralic deposits composed of very fme-to fine-grained
sandstone; color light yellowish brown to brown to brownish yellow.
Santiago Formation. Uppermost unit. Variegated brown and reddish brown ("red")
fossiliferous mudstone, grading down to include sandstone stringers. Fossils
represented by SDSNH locs. 6816 and 6817.
Santiago Formation. Middle unit. Fossiliferous silty very fine-grained sandstone
unit; color light olive gray to pale olive (5Y 6/2-6/3), becomes white when dry. Iron
oxide streaks; massive, consolidated, poorly friable. Fossils represented by SDSNH
loc. 6818.
Santiago Formation. Lowermost unit. Fossiliferous light gray to pale yellow (5Y
7/2-7/3) clayey siltstone, grading upward (by elevation of 261 feet AMSL) to light
brownish gray (1 OYR 6/2) with white blotching. This, in turn, grades upward to
brown (7.5 YR 5/2) ("purple") to upper contact. Generally massive, except the
uppermost foot is poorly bedded and bioturbated; sediments exhibit soft-sediment
deformation within silt interbeds, and scattered gravel-sized bentonite clay clasts.
Fossils found only in upper four feet of unit. Fossils represented by SDSNH loc.
6819.
3.0-1
Elev.
282'
278'
274'
270'
266'
262'
258'
254'
I
Graphic
Column
Fossil
Locality
6816.
6817.
6818.
6819.
Lithographic
Description
Lower to middle Pleistocene paralic deposits
Light yellowish brown to brown to brownish
yellow, very fine-to fine-grained sandstone.
Middle Eocene Santiago Formation
Variegated brown and reddish brown ("red")
mudstone grading down to include sandstone
stringers. SDSNH locs. 6816 and 6817.
Olive gray to pale olive, silty, very [me-
grained sandstone. SDSNH loc. 6818.
Light gray to pale yellow clayey siltstone
(mudstone) grading upward by elevation
261 feet to light brownish gray with white
blotching. This, in turn, grades upward to
brown ("purple") to upper contact.
Invertebrate marine fossils found in top
four feet only. SDSNH loc. 6819.
Figure 3.0-1
Stratigraphic Column
The Tabata Ranch Project
3.0-2
Paleontological Monitoring Report, Tabata Ranch Project
3.2 Fossil Localities: The multiple field collections made during monitoring of grading
and excavation activities have been assigned to four SDNHM localities and represent three
stratigraphic levels, from top (SDSNH locs. 6816 and 6817), middle (SDSNH loc. 6818), and
bottom (SDSNH loc. 6819). The relative positions of these are shown on both the stratigraphic
section for the project (Figure 3.0-1) and the fossil locality map (Figure 3.0-2).
3.2.1 SDSNH loc. 6816: Middle Eocene, Santiago Formation, informal member
"B." Marine invertebrate fossils recovered from estuarine mudstones exposed in the cut slope of
house lot 3 (City of Carlsbad, Engineering Department, Project No. CT 06-15, Drawing No. 471-
9A) on the east side of the cul-de-sac at the south end of Strawberry Place, in the "Tabata
Ranch" minor housing subdivision in the city of Carlsbad, San Diego County, California (Figure
3.0-2). On the U. S. Geological Survey, 7.5-minute, 1:24,000-scale Encinitas, California
topographic quadrangle map (1968, photorevised 1975), the subject property is located in the
very northeast corner of Section 28, Township 12 South, Range 4 West, San Bernardino Base
and Meridian (Figure 1.0-2). Based on Google Earth imagery (January 2016), the approximate
UTM coordinates (Zone 11 South) for this locality are: 472115 mE., 3663460 m N. The fossils
were collected at an approximate elevation of272 feet AMSL (M. K. Klinger field notes).
The sediments at SDSNH loc. 6816 are stratigraphically equivalent to those from
SDSNH loc. 6817, q. v., and represent the highest fossiliferous horizon of the three that were
recognized during paleontological monitoring for the project (see stratigraphic column, Figure
3.0-1). Sediments mainly consisted of variegated brown and reddish brown fossiliferous clayey
siltstone (see Subsection 3.1 ).
Fossils were collected by Mary K. Klinger (field number MKK-TB-01) on 9 July 2014.
Copies of all field notes and maps have been included with the fossil locality data provided to the
SDNHM with the fossil collection.
3.2.2 SDSNH loc. 6817: Middle Eocene, Santiago Formation, informal member
"B." Marine invertebrate fossils recovered from estuarine mudstones exposed in the cut slope
west of house lot 1 (City of Carlsbad, Engineering Department, Project No. CT 06-15, Drawing
No. 471-9A) on the east side of Strawberry Place where it bends from east-west to north-south,
in the "Tabata Ranch" minor housing subdivision in the city of Carlsbad, San Diego County,
California (Figure 3.0-2). On the U. S. Geological Survey, 7.5-minute, 1:24,000-scale Encinitas,
California topographic quadrangle map (1968, photorevised 1975), the subject property is
located in the very northeast corner of Section 28, Township 12 South, Range 4 West, San
Bernardino Base and Meridian (Figure 1.0-2). Based on Google Earth imagery (January 2016),
the approximate UTM coordinates (Zone 11 South) for the multiple locality collections from
SDSNH loc. 6817 are: 472085 m E., 3663527 m N. (between 472075 and 472090 mE., and
between 3663530 and 3663518 m N.). Fossils were collected in the area of the retention basin
and berm along the outer, northeast, corner of Strawberry Place (Figure 3.0-2). The elevational
range for the upper fossiliferous horizon at this locality is approximately 270 to 273 feet AMSL.
The sediments at SDSNH loc. 6817 are stratigraphically equivalent to those from
SDSNH loc. 6816, q. v., and represent the highest fossiliferous horizon of the three that were
recovered during paleontological monitoring for the project (see stratigraphic column, Figure
3.0-3
Paleontological Monitoring Report, Tabata Ranch Project
3.0-1). Sediments mainly consisted of variegated brown and reddish brown fossiliferous clayey
siltstone (see Subsection 3.1).
Fossils were collected by Jeffrey K. Hemy (field number JH-TR-01, here assigned) on 20
June 2014; Todd A. Wirths (field number TW-TR-03) on 24 and 25 June 2014; James S. Shrieve
(field number JS-TR-01) on 30 June 2014; and Claire M. Allen (field numbers CA-TR-01
through -07) on 15 July 2014. Copies of all field notes and maps have been included with the
fossil locality data provided to the SDNHM with the fossil collection.
3.2.3 SDSNH foe. 6818: Middle Eocene, Santiago Formation, informal member
"B." Marine invertebrate fossils recovered from estuarine mudstones exposed in the cut slope
west of house lot 1 (City of Carlsbad, Engineering Department, Project No. CT 06-15, Drawing
No. 471-9A) on the east side of Strawberry Place where it bends from east-west to north-south,
in the "Tabata Ranch" minor housing subdivision in the city of Carlsbad, San Diego County,
California (Figure 3.0-2). On the U. S. Geological Survey, 7 .5-minute, 1 :24,000-scale Encinitas,
California topographic quadrangle map (1968, photorevised 1975), the subject property is
located in the very northeast comer of Section 28, Township 12 South, Range 4 West, San
Bernardino Base and Meridian (Figure 1.0-2). Based on Google Earth imagery (January 2016),
the approximate UTM coordinates (Zone 11 South) for the multiple locality collections from
SDSNH loc. 6818 are: 472085 mE., 3663527 m N. (between 472075 and 472090 mE., and
between 3663530 and 3663518 m N.). Fossils were collected in the area of the retention basin
and berm along the outer, northeast, comer of Strawberry Place (Figure 3.0-2). The elevational
range for the middle fossiliferous horizon at this locality is approximately 264 to 270 feet AMSL
(Figure 3.0-1 ).
The sediments at SDSNH loc. 6818 are stratigraphically below those of SDSNH loc.
6817 and above those for SDSNH loc. 6819, and represent the middle fossiliferous horizon of
the three that were recovered during paleontological monitoring for the project (see stratigraphic
column, Figure 3.0-1). Sediments mainly consisted of light olive gray to pale olive,
fossiliferous, silty, very fine-grained sandstone (see Subsection 3.1).
Fossils were collected by Todd A. Wirths (field number TW-TR-02) on 24 and 25 June
2014. Copies of all field notes and maps have been included with the fossil locality data
provided to the SDNHM with the fossil collection.
3.2.4 SDSNH foe. 6819: Middle Eocene, Santiago Formation, informal member
"B." Marine invertebrate fossils recovered from estuarine mudstones exposed in the cut slope
west of house lot 1 (City of Carlsbad, Engineering Department, Project No. CT 06-15, Drawing
No. 471-9A) on the east side of Strawberry Place where it bends from east-west to north-south,
in the "Tabata Ranch" minor housing subdivision in the city of Carlsbad, San Diego County,
California (Figure 3.0-2). On the U.S. Geological Survey, 7.5-minute, 1:24,000-scale Encinitas,
California topographic quadrangle map (1968, photorevised 1975), the subject property is
located in the very northeast comer of Section 28, Township 12 South, Range 4 West, San
Bernardino Base and Meridian (Figure 1.0-2). Based on Google Earth imagery (January 2016),
the approximate UTM coordinates (Zone 11 South) for the multiple locality collections from
SDSNH loc. 6819 are: 472085 mE., 3663527 m N. (between 472075 and 472090 mE., and
3.0-4
Paleontological Monitoring Report, Tabata Ranch Project
between 3663530 and 3663518 m N.). Fossils were collected in the area of the retention basin
and berm along the outer, northeast, corner of Strawberry Place (Figure 3.0-2). The elevational
range for the lowest fossiliferous horizon at this locality is approximately 260 to 264 feet AMSL
(Figure 3.0-1).
The sediments at SDSNH loc. 6819 are stratigraphically below those of SDSNH loc.
6818, and represent the lowest fossiliferous horizon of the three that were recovered during
paleontological monitoring for the project (see stratigraphic column, Figure 3.0-1). Sediments
mainly consisted oflight gray to pale yellow, fossiliferous, clayey siltstone (see Subsection 3.1).
Fossils were collected by Todd A. Wirths (field number TW-TR-01) on 24 and 25 June
2014. Copies of all field notes and maps have been included with the fossil locality data
provided to the SDNHM with the fossil collection.
3.0-5
VJ
~
Legend
~~
1
D Project Boundary
0 40 80ft
I -0 10 20m
J
Figure 3.0-2
Fossil Locality Map
The Tabata Ranch Project
Paleontological Monitoring Report, Tabata Ranch Project
3.3 Laboratory Preparation: Fossils collected in the field were returned to the
laboratory facility of BFSA in cardboard flats or five-gallon plastic buckets. All buckets and
trays are marked in the field with a unique field number, the collector's name, and the date
collected. The material from the project site consisted of several large blocks of fossiliferous
matrix, and smaller pieces with exposed specimens on their surface(s). The larger blocks were
broken apart using a steel chisel set into a hand-operated arbor press, which yielded more
manageably sized pieces that could be examined for exposed fossil impressions. Matrix pieces
with individual exposed fossils could then be trimmed of extra matrix using a Makita handheld
diamond-bladed trim saw. This method is ideal because there is no fracturing of the specimen,
as happens when a hammer and chisel are used to remove extraneous matrix to reduce the size of
the specimen. Small hand tools, such as dental picks, are then used to expose the edges of the
fossils, particularly around the hinge area of the clams, and around the aperture of the
gastropods. The sedimentary matrix from the clayey siltstone horizons was not indurated
(cemented), but was tight and did not tend to friability, and thus, did not need to be strengthened
with a consolidant. The silty very fine-grained sandstone specimens, however, were somewhat
friable and tended to shed surface particles when handled. These specimens were soaked in a
mixture of Paraloid B-72, an acrylic plastic, which had been dissolved in acetone (a carrier).
Because of the low surface tension of acetone, it easily penetrates the specimen matrix, but also
dries very quickly, leaving behind a stabilized and hardened specimen.
Specimens are then sorted taxonomically (to species level if possible) and identified.
Identifications are based on the paleontologist's years of experience with the Eocene fossil
record of San Diego and are aided by publications on Eocene fossils from other southern
California locations. After the fossils are sorted to species and identified, each specimen or
species lot (all of the specimens of a single species from a single locality) is/are assigned
SDSNH specimen numbers. Both the SDSNH locality number and the specimen/species lot
number are written on tiny patches of white enamel or acrylic paint in waterproof India ink.
Labels are then printed on archival paper and the species identification, including author and date
published, and specimen number are added to each label. When organized, the fossils are then
deposited in the Department of Paleontology at the SDNHM in Balboa Park. The museum, for a
nominal fee, accepts the collection and promises to conserve the fossils for perpetuity and make
them available for examination or study by the lay public, interested students, or professional
paleontologists (see the SDNHM's letter of acceptance in Section 6.0).
3.4 Paleontology: Although a diverse array of fossil shells from locally unweathered
parts of the Santiago Formation are known to be exquisitely preserved (cf SDNHM collections,
especially from the Vista area), the diversity of species from the Tabata Ranch localities is
relatively low, which is due in part to chemical weathering of shells preserved in the finer-
grained sediments and the estuarine paleoenvironment represented by the fossils. Estuarine
invertebrate faunas, both modern and fossil, tend to have a low diversity of organisms, but often
a great abundance of actual individuals. Nevertheless, the recovered fauna (Table 3.0-1)
represents a significant addition to our knowledge of the local estuarine marine life that existed
during middle Eocene time.
The collective fauna from the collections that were made during paleontological
monitoring ofthe project (Table 3.0-1, SDSNH locs. 6816 through 6819) includes more than 33
3.0-7
Paleontological Monitoring Report, Tabata Ranch Project
species of marine invertebrates, which consist of at least 18 species of bivalve mollusks, at least
12 species of gastropods, one inarticulate brachiopod, and crab and mantis shrimp remains.
Most of the invertebrate species are represented by internal and external molds preserved in a
compact, tight, clayey siltstone or silty very fine-grained sandstone matrix. Internal and external
molds of a number of unclassified gastropods and smooth-shelled bivalves were also present, but
were not complete enough nor well enough preserved to be identified.
The faunas from the four localities are generally similar, but vary in the relative
abundances of several species. SDSNH locs. 6816 and 6817 represent the stratigraphically
highest fossiliferous horizon, whereas SDSNH locs. 6818 and 6819 represent the
stratigraphically middle and lower horizons, respectively (Figure 3.0-1). Bivalves are about
evenly distributed among all four localities, each with six or seven species apiece, although the
upper fossiliferous horizon had a total of 12 or more identified bivalve species. Interestingly,
eight and nine species of gastropods were recovered from the two upper clayey siltstone
localities, respectively, whereas only a single species (the cap shell Calyptraea diegoana) was
present in the collection from the silty, very fine-grained sandstone horizon. This would appear
to be an environmentally controlled phenomenon, although the lowest clayey siltstone horizon
only yielded two identifiable gastropod species.
Overall, the most common species in the upper and lower finer-grained clayey siltstone
horizons is the mussel Brachidontes cowlitzensis, whereas the pteriomorph Pteria clarki is
relatively common in the upper horizon, and the tellinid Macoma sp., cf. M sheridani is
relatively common in the lowermost unit. In the middle, silty, very fine-grained sandstone
horizon, the tellinid Tellina cowlitzensis, the mactrid Spisula bisculpturata, and the venerids
Macrocallista conradiana and Pitar uvasana are all relatively common. None of the gastropod
species are particularly abundant in any of the collections.
The faunas from all of the collecting sites are suggestive of protected, soft-bottom
estuarine conditions and deposition in a low energy, shallow, subtidal bay or lagoonal
environment protected from wave action, as might be found along the open coast. The faunas
from the project site are similar in composition to other estuarine faunas documented from
exposures of the Santiago Formation in northern San Diego County (cf SDNHM collection
records). The most unusual species, if correctly identified, is the inarticulate brachiopod
Glottidia sp., which was previously unknown from local Eocene deposits. Two specimens of
this species were recovered from the uppermost fossiliferous horizon at SDSNH loc. 6816.
Another rare species is the bivalve Tellina cowlitzensis, described from the Pacific Northwest,
but only previously recorded from the San Diego area by Kennedy et al. (2012, 2013) from the
Mission Valley Formation. The species was only found in the middle, silty, very fine-grained
sandstone horizon (SDSNH loc. 6818). Among the gastropods, the wentletrap Amaea sp. is also
particularly rare in San Diego Eocene deposits (SDSNH loc. 6816).
All of the fossils from SDSNH locs. 6816 through 6819 have been deposited in the
collections of the SDNHM in Balboa Park (see Section 6.0) and bear SDSNH specimen I species
lot numbers 141400 through 141467.
3.0-8
Paleontological Monitoring Report, Tabata Ranch Project
Table 3.0-1
List of middle Eocene marine fossils from the Santiago Formation (informal member
"B") recovered during paleontological monitoring of grading and excavation activities at the
Tabata Ranch minor housing subdivision project site in Carlsbad, San Diego County, California
(SDSNH lacs. 6816 through 6819). Abbreviations: x, present; cf, compare with; sp., species
(unidentified); indet., indeterminate. Identifications by N. S. Rugh.
Species 6816 6817 6818 6819
Mollusca: Bivalvia (clams)
Acanthocardia brewerii (Gabb, 1864) X X
Arcopsis hornii (Gabb, 1864) X X
Brachidontes cowlitzensis (Weaver & Palmer, 1922) X X X
Gari sp., cf. G. texta Gabb, 1864 X
cf. Gari sp., indet. X
Glycymeris sp., cf. G. rosecanyonensis (Hanna, 1927) X
cf. Macoma sheridani (Vokes, 1939) X
Macrocallista conradiana (Gabb, 1864) X X X
Macrocallista sp., cf. M. tecolotensis (Hanna, 1927) X
cf. Macrocallista spp., indet. X
Miltha packi (Dickerson, 1916) X
? Mytilidae, indet. X
Periploma eodiscus (Vokes, 1939) X
Periploma sp., indet. X X
Pitar uvasana (Conrad, 1855) X
? Pitar sp., indet. X
Pteria clarki (Weaver and Palmer, 1922) X X
Spisula bisculpturata (Anderson and Hanna, 1925) X
Tellina cowlitzensis (Weaver, 1916) X
Tellina sp., indet. X X X
Thracia sorrentoensis (Hanna, 1927) X
V eneroida, indet. X X X
Bivalvia, indet. (unidentified internal and external molds) X X
Mollusca: Gastropoda (snails)
Amaea sp., indet. X
Calyptraea diegoana (Conrad, 1855) X X
Conus hornii (Gabb, 1864) X
Crepidula pileum (Gabb, 1864) X
Fissurellidae, indet. X
Janiopsis sanmarcosensis (Givens and Kennedy, 1976) X X
Olequahia domenginica (Vokes, 1939) X X
cf. Pseudoperissolax sp., indet. X
3.0-9
Paleontological Monitoring Report, Tabata Ranch Project
Species
Ranellina pilsbryi (Stewart, 1927)
Sinum obliquum (Gabb, 1864)
Turritella uvasana (Conrad, 1855
Whitneyella markleyensis (Clark, 1938)
Gastropoda, indet. (unidentified internal and external molds)
Brachiopoda: Inarticulata (lamp shells)
Glottidia sp., indet. .
Arthropoda: Crustacea: Malacostraca (crabs and relatives)
Callianassidae, indet.
Decapoda, indet. (crab claw)
Crustacea?
Plants I Vegetative material (plant debris)
Wood fragment
Incertae sedis (fossils of uncertain affinity)
Incertae sedis
SDSNH loc. 6816: specimen numbers 141400-141421
SDSNH loc. 6817: specimen numbers 141422-141443
SDSNH loc. 6818: specimen numbers 141444-141452
SDSNH loc. 6819: specimen numbers 141453-141467
3.0-10
6816 6817 6818 6819
X X
X X X
X X
X X
X X X
X
X X
X
X
X
X
Paleontological Monitoring Report, Tabata Ranch Project
4.0 SUMMARY
Paleontological mitigation measures initiated in response to environmental mitigation
requirements for a mitigated negative declaration for preconstruction grading and excavation
activities related to construction of the Tabata Ranch housing subdivision project (CT 06-15)
have been satisfactorily completed. The project site is located north of Poinsettia Lane and west
of Aviara Parkway and encompasses five new house sites off of Strawberry Place (new street)
and Lemon Leaf Drive in the city of Carlsbad, San Diego County, California.
Paleontological monitoring of earth-moving activities was conducted intermittently, as
needed, between late March and mid-July of 2014, and resulted in the discovery of richly
fossiliferous exposures in estuarine mudstone beds within the middle Eocene (~ 46 to ~ 42
million year old) Santiago Formation (informal "member B"). Marine invertebrate fossils were
obtained from multiple field collections that have been assigned to four museum localities
(Figure 3.0-2), all of which were collected from cut slopes along Strawberry Place (new street)
in Carlsbad, San Diego County, California (Figure 1.0-2).
The faunas from all of the collecting sites have been assigned to four museum localities
and three stratigraphic levels (Table 3.0-1, SDSNH locs. 6816 through 6819). Although similar
in species makeup, they differ somewhat in the relative abundances of particular species.
Collectively, the combined fauna is represented by at least 33 species of marine invertebrates,
divided among at least 18 species of bivalve mollusks, at least 12 species of gastropods, one
inarticulate brachiopod, and decapod crustacean remains (crab and mantis shrimp). Internal and
external molds of a number of additional unidentified gastropods and smooth-shelled bivalves
were also present. Most of the invertebrate species are represented by internal and external
molds preserved in a tight, moderately compact, very fine-grained mudstone and silty sandstone
matrix. No vertebrate fossils (e.g., fish remains) were recovered from either sedimentary unit.
Overall, the most common species in the upper and lower finer-grained clayey siltstone
horizons is the mussel Brachidontes cowlitzensis, whereas the pteriomorph Pteria clarki is
relatively common in the upper horizon, and the tellinid Macoma sp., cf. M sheridani is
relatively common in the lowermost unit. In the middle, silty, very fme-grained sandstone
horizon, the tellinid Tellina cowlitzensis, the mactrid Spisula bisculpturata, and the venerids
Macrocallista conradiana and Pitar uvasana are all relatively common. None of the gastropod
species was particularly abundant in any of the collections.
Fossils collected during the paleontological monitoring program have been fully prepared
(broken out and cleaned of adhering matrix, stabilized with Paraloid B-72, and repaired, if
necessary) and curated (sorted, identified, catalogued, painted, numbered, and labeled) and
deposited in the Department of Paleontology at the SDNHM in Balboa Park, San Diego, where
they will receive long-term archival care and conservation (see letter of collections receipt in
Section 6.0). Fossils from SDSNH locs. 6816 through 6819 have been assigned SDSNH
specimen I species lot numbers 141400 through 141467. The specimens are thus available for
future study or examination at any time by the lay public, students, or professional
paleontologists.
4.0-1
Paleontological Monitoring Report, Tabata Ranch Project
5.0 REFERENCES CITED
Browne, I. D., and Demere, T. A. 2006. Paleontological mitigation report neighborhoods 1.16
& 1.17 The Greens City of Carlsbad San Diego County, California. Unpublished
monitoring report prepared for Morrow Development, Carlsbad, by the Department of
Paleo Services, San Diego Natural History Museum, San Diego.
Demere, T. A., and Walsh, S. L. 1993. Paleontological resources -County of San Diego.
Unpublished report prepared for the San Diego County Department of Public Works, San
Diego, by the Department of Paleontology, San Diego Natural History Museum. Pp. i-iii
+ 1-68, figs. 1-3, 8 maps.
Givens, C. R., and Kennedy, M.P. 1976. Middle Eocene mollusks from northern San Diego
County, California. Journal ofPaleontology, 50(5): 954-975, figs. 1-2, pls. 1-4, tables
1-2.
Kennedy, G. L., and Shiller, G. I. 2009. Paleontological monitoring report, construction of
Avellino project (La Costa Greens neighborhood 1.16), Carlsbad, San Diego County,
California. Unpublished paleontological monitoring report prepared for KB Home
Coastal, Inc., Wildomar, by Brian F. Smith and Associates, Inc., Poway.
Kennedy, M.P., and Tan, S. S. 2005. Geologic map of the Oceanside 30' x 60' quadrangle,
California. California Geological Survey, Regional Geologic Map Series, 1:100,000
scale, Map No.2: sheets 1-2 (scale 1:100,000).
Kennedy, G. L., Rugh, N. S., and Wirths, T. A. 2013. Paleontological monitoring report,
Village Lindo Paseo Dormitories, SDSU College area, city of San Diego, San Diego
County, California. Unpublished paleontological monitoring report prepared for Village
Lindo Paseo, L.P., San Diego, by Brian F. Smith and Associates, Inc., Poway.
Kennedy, G. L., Shiller, G. I., and Rugh, N. S. 2012. Paleontological monitoring report, Sewer
and Water Group 792, En canto, city of San Diego, San Diego County, California.
Unpublished paleontological monitoring report prepared for Burtech Pipeline, Inc.,
Encinitas, by Brian F. Smith and Associates, Inc., Poway.
Shiller, G. I., and Kennedy, G. L. 2003. Paleontological monitoring report, Morning Ridge
project (DeJong property), city of Carlsbad, San Diego County, California. Unpublished
paleontological monitoring report prepared for Keystone Communities, San Diego, by
Brian F. Smith and Associates, Poway.
Squires, R. L., and Saul, L. R. 2002. New information on Late Cretaceous, Paleocene, and
Eocene neritid gastropods from the North American Pacific slope. The Veliger, 45(3):
177-192, figs. 1-40.
Stephenson, R. A., Giffen, J. H., and Gibson, E. E. 2009. County of San Diego guidelines for
determining significance [for] paleontological resources. Unpublished report prepared
5.0-1
Paleontological Monitoring Report, Tabata Ranch Project
for internal use by the San Diego County Land Use and Environment Group, Department
ofPlanning and Land Use and Department of Public Works, San Diego. Pp. i-vi + 1-47,
figs. 1-10, table 1.
Tan, S. S., and Kennedy, M.P. 1996. Geologic maps of the northwestern part of San Diego
County, California. California Division of Mines and Geology, DMG Open-File Report
96-02: pls. 1-2 (map sheets, scale 1:24,000, with limited text).
5.0-2
6.0 APPENDIX
Paleontological Monitoring Report, Tabata Ranch Project
LETTER OF COLLECTIONS RECEIPT FROM THE
SAN DIEGO NATURAL HISTORY MUSEUM
6.0-1
r
SAN DIEGO NATURAL HISTORY MUSEUM
BALBOA PARK-SAN DIEGO SOCIETY OF NATURAL HISTORY -ESTABLISHED 1874
11 March 2016
Mr. Brian F. Smith
Brian F. Smith & Associates
14010 Poway Road, Suite A
Poway, CA 92064
RE: Acceptance of the Tabata Ranch, 2016 Paleontological Collection
Dear Mr. Smith:
This letter is to acknowledge receipt of the fossils salvaged during excavation activities
for the Tabata Ranch project located within the City of Carlsbad, California. It is my
understanding that the project owner "Groundwurk, Inc.", 2442 Second Avenue, San Diego, CA
92101, is donating the fossils to the San Diego Natural History Museum.
As noted in documents submitted with the fossils, the excavations into native
sedimentary deposits at the Tabata Ranch project site resulted in the discovery of four primary
collection sites that have been assigned SDSNH locality numbers 6816 through 6819. SDSNH
specimen/species lot numbers for these collections include 141400 through 141467. These
recovered specimens represent an important paleontological resource and when curated into the
research collections of the Museum the fossils will be made available to scientists and students
for further study. In accepting the Tabata Ranch paleontological collection, the Museum makes
a commitment to curate and store the fossils in perpetuity in the public trust.
Sincerely,
Melissa Soetaert
Contract Administrator
Department ofPaleontology
Post Office Box 121390 *San Diego, California 92112-1390 *Telephone 619-255-0232 *FAX 619-255-0187 * www.sdnhm.org