San Timoteo Formation

Part of the wider San Timoteo Badlands, San Timoteo Formation was initially excavated in San Timoteo Canyon under by a team sponsored by Childs Frick from 1916 to 1921.{{Cite news |date=1918-03-07 |title=The Bone Mine |url=https://www.newspapers.com/article/the-banning-record-the-bone-mine/135338030/ |access-date=2023-11-17 |work=The Banning Record |pages=2}}{{Cite book |last1=Albright |first1=L. Barry |url=http://california.universitypressscholarship.com/view/10.1525/california/9780520098367.001.0001/upso-9780520098367 |title=Biostratigraphy and Vertebrate Paleontology of the San Timoteo Badlands, Southern California |last2=Kendall, Jr. |first2=Arthur |date=2000-08-03 |publisher=University of California Press |isbn=978-0-520-09836-7 |doi=10.1525/california/9780520098367.003.0001}}

The San Timoteo Formation represents Pliocene and Early Pleistocene sediments, mostly sandstone. The Formation overlies the late Miocene and early Pliocene Mt. Eden Formation (Jack Rabbit Trail & Eden Hot Springs localities, corresponding to the Hemphillian and Blancan faunal stages).

Fossils of Irvingtonian prehistoric mammals were found in the San Timoteo Formation (El Casco, Mammoth and Shutt Ranch localities).{{Cite web |title=San Timoteo Badlands |url=https://www.utep.edu/leb/pleistnm/sites/santimoteo.htm |access-date=2024-07-22 |website=www.utep.edu}}{{Cite web |title=Big Pine Citizen 2 March 1918 — California Digital Newspaper Collection |url=https://cdnc.ucr.edu/?a=d&d=BPC19180302.2.28 |access-date=2023-11-17 |website=cdnc.ucr.edu}}{{Cite web |last=McComas |first=Katie |date=8 May 2019 |title=Paleontological Records Search – Gilman Springs Median and Shoulder Widening Project |url=https://static1.squarespace.com/static/5b7321a489c17291c4fd7b75/t/622b945e6eddcc15103a5a88/1647023200780/PaleontologicalRecordsSearchMemo_May2019.pdf |via=San Diego Natural History Museum}} These include:

• Canis edwardii (Edward's wolf)
• Microtus sp. (vole)
• Ondatra idahoensis (muskrat)
• Mictomys kansasensis (bog lemming)
• Erethizon cascoensis (porcupine)
• “Plesippus” fracescana (three-toed horse)
• Equus bautistensis (horse)
• Tapirus merriami (tapir)
• Odocoileus cascaensis (deer)
• Megalonyx sp. (ground sloth)
• Mammuthus sp. (mammoth)
• Possibly a giant bear (may be either Arctodus or Agriotherium){{Cite journal |last1=Scott |first1=Eric |last2=Cox |first2=Shelley M. |date=May 24, 1993 |title=Arctodus simus (Cope, 1879) from Riverside County, California |url=https://ucmp.berkeley.edu/science/paleobios/backissues/v15no2_scott&cox.pdf |journal=PaleoBios |volume=15 |issue=2 |pages=27–36}}

Fossils have also been recovered from the El Casco Substation locality, which was dated to 1.4Mya. Recovered specimens include Smilodon gracilis, Homotherium, two ground sloths, two types of camels, a llama, horse, and deer. Plant fossils include birch, pine, sycamore and oak trees.{{Cite web |date=2010-09-24 |title=The Associated Press: Calif. utility stumbles on 1.4M-year-old fossils |url=http://www.google.com/hostednews/ap/article/ALeqM5hUkul_DVGCUiaQPkJB51InmsCnrAD9IC5GN80 |access-date=2024-07-23 |archive-url=https://web.archive.org/web/20100924050705/http://www.google.com/hostednews/ap/article/ALeqM5hUkul_DVGCUiaQPkJB51InmsCnrAD9IC5GN80 |archive-date=2010-09-24 }}{{Cite web |title=El Casco Substation |url=https://lsa.net/project/el-casco-substation/ |access-date=2024-07-23 |website=LSA |language=en-US}}{{Cite web |title=Southern California Edison Discovers Most Comprehensive Collection of Fossils of its Era in Southern California |url=https://newsroom.edison.com/releases/southern-california-edison-discovers-most-comprehensive-collection-of-fossils-of-its-era-in-southern-california |access-date=2024-07-23 |website=Edison International {{!}} Newsroom |language=en}}

{{Portal|Earth sciences|California|Paleontology|}}

• List of fossiliferous stratigraphic units in California
• Paleontology in California

{{Reflist}}

• {{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}}

Category:Geologic formations of California

{{California-geologic-formation-stub}}