HomeMy WebLinkAboutCT 99-08; Spyglass II; Tentative Map (CT) (28)Sen+_By: WILSON ENGINEERING; 7604380173; Apr-16-01 8:47AM; Page 2/3
01/11/01 «t, ,iST H 0248 3D NAT HIST WISE
San Diego Natural History Museum
Ualbou Pwi-k • ton tjltRO Sodcvy or Pfcuural HiKOiy • Rs«ahluih«<l 1H74
16 April 2001
Mr. Robert CLadwig RECEIVED
Ladwig Design Group, Inc. ABB * fi
703 Palomar Airport Road, Suite 300 M™ ] °
Carlsbad, CA 92009 LADW,Q
RE: Paleontologies! Resources, Spyglass H Carlsbad, CA
Dear Bob:
This letter report summarizes the results of my palcontological resource assessment of the
above referenced project. Assessment is based upon a review of existing published and
unpublished geological literature (Weber 1982; California Division of Minos and Geology Open-
File Report 82-12; Eisenbcrg, 1983), and a review of museum palcontological records (San Diego
Natural History Museum). A walkover of the site was conducted on 14 April 2001 to field check
the results of the literature and records searches.
The 10-acre project site is located at the southeast comer of El Camino Real and Carlsbad
Village Drive in the City of Carlsbad. The northern portion of the site was previously graded, but
has been left to erode over the subsequent years. Several road cuts occur along (he western portion
of the site adjacent to Bl Camino Real, The headword portion of a tributary drainage to Buena
Vista Creek occurs in the central region of the site. Elevations range from approximately 139 feet
above sea level in the northwestern comer of the site to approximately 269 feet in the southeastern
portion of the site.
The on-site geology consists of Eocene-age sandstones and mudstones of the Santiago
Formation locally overlain by Pleistocenc-agc unnamed sandstones and conglomerates. Good
exposures of the Santiago Formation occur in some of the eroded cut slopes created during the
original grading of the site. These exposures typically consist of white to gray-green, coarse-
grained and fine-grained, massive fluvial sandstones with lesser amounts of light brown mudstones.
A 40-foot-high road cut along £1 Camino Real in the southwestern corner of the site exposes whit*,
coarse-grained, massive, fluvial sandstones of the Santiago Formation overlain by a Pleistocene
alluvial/fluvial sequence of gray and brown, coarse-grained sandstones and cobble conglomerates.
The Pleistocene sandstones and conglomerates occur as a 20-foot thick sedimentary lease thai was
deposited in a broad fluvial channel.
No fossil remains were discovered on-site during the field walkover and no previous
palcontological collecting localities were noted in museum records. However, there are a number
of recorded paleontological localities within a two-mile radius of the site. These localities occur in
the Santiago Formation and have produced important skeletal remains of land mammals including
carnivore, rodent, rhinoceros, brontothere (large extinct rhino like browser), and protoreodont
(small extinct deer like browser). These fossil mammal remains are very significant and represent
one of the richest sources of paleontological information about Eocene life in California.
Based on the proven paleontological resource value of the Santiago Formation and the .
potential paleontological resource value of the unnamed Pleistocene deposits, it is suggested that , -)
development of the project site has the potential to create significant impacts to paleontological i Q
I uffto Box 121390 • San Dlcgo, Ulifotftb 92112-1390 . Telephone 619-H2-3W1 • fax G19-J3WHW .
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Sent By: WILSON ENGINEERING; 7604380173; Apr-16-01 8:48AM; Page 3/3
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resources. These potential impacts will occur when mass excavation activities cut into the Santiago
Formation and the unnamed Pleistocene deposits.
Implementing the following measure can ensure mitigation of Sic impacts discussed above:
[1] Prior to initiation of construction activities the project developer shall retain a qualified
paleontologist to carry out the mitigation program outlined here, (A qualified paleontologist is
defined as an individual with a MS or Ph.D. in paleontology or geology who is familiar with
paleontological procedures and techniques.)
[2] A qualified paleontologist shall be at the pre-conatruction meeting to consult with the
grading and excavation contractors.
[3] A paleontological monitor shall be onsfte at all times during the original cutting of
previously undisturbed deposits of me Santiago Formation to inspect exposures for contained
fossils. Grading in the unnamed Pleistocene deposits shall be monitored on a half-time basis. (A
paleontological monitor is defined as an individual who has experience in the collection and
salvage of fossil materials. The paleontologkal monitor shall woik under the direction of a
qualified paleontologist)
[4] When fossils are discovered, the paleontologist (or paleontological monitor) shall
recover tfvem. m most oases this fossil salvage can be completed in a short period of time.
However, some fossil specimens (such as a complete large mammal skeleton) may require an
extended salvage period. In these instances the paleontologist (or paleontological monitor) shall be
allowed to temporarily direct, divert, or halt grading to allow recovery of fossil remains in a timely
manner. Because of the potential for the recovering of small fossil remains, such as isolated teeth
of small ttwHtyifrfc (e.g., rodents and primates), it may be necessary to collect bulk matrix samples
for off-site screen-washing.
[5] Fossil remains collected during the monitoring and salvage portion of the mitigation
program shall be cleaned, repaired, sorted, and cataloged.
[6] Prepared fossils, along with copies of all pertinent field notes, photos, and maps, shall be
deposited (as a donation) in a scientific institution with permanent paleontological collections such
as the San Diego Natural History Museum. Donation of the fossils shall be accompanied by
financial support for initial specimen storage.
[1] A final summary report shall be completed mat outlines the results of the mitigation
program, This report shall include discussions of the methods used, stratigraphic section^)
exposed, types of fossils collected, and significance of recovered fossils. An inventory of curated
specimens listing catalogue numbers shall also be included.
In summary, the project site possesses a potential for producing significant paleontological
resources. Development of the project site will result in impacts to these resources. The measures
proposed above will ensure proper mitigation of these impacts. Please feel free to contact me if
you have any questions concerning my findings.
Sincerely yours,
Thomas A. Demure, Ph.D.
Department of Paleontological Services