San Timoteo Formation Explained

San Timoteo Formation
Type:	Formation
Region:	California
Country:	United States

The San Timoteo Formation, also called the San Timoteo Beds, is a geologic formation in California.

History

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.^{[1] [2]}

Geology

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

Fossils of Irvingtonian prehistoric mammals were found in the San Timoteo Formation (El Casco, Mammoth and Shutt Ranch localities).^{[3] [4] [5]} 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)^[6]

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.^{[7] [8] [9]}

See also

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

References

• Web site: Fossilworks: Gateway to the Paleobiology Database. ((Various Contributors to the Paleobiology Database)). 17 December 2021.

Notes and References

1. News: 1918-03-07 . The Bone Mine . 2023-11-17 . The Banning Record . 2.
2. Book: Albright . L. Barry . Biostratigraphy and Vertebrate Paleontology of the San Timoteo Badlands, Southern California . Kendall, Jr. . Arthur . 2000-08-03 . University of California Press . 978-0-520-09836-7 . 10.1525/california/9780520098367.003.0001.
3. Web site: San Timoteo Badlands . 2024-07-22 . www.utep.edu.
4. Web site: Big Pine Citizen 2 March 1918 — California Digital Newspaper Collection . 2023-11-17 . cdnc.ucr.edu.
5. Web site: McComas . Katie . 8 May 2019 . Paleontological Records Search – Gilman Springs Median and Shoulder Widening Project . San Diego Natural History Museum.
6. Scott . Eric . Cox . Shelley M. . May 24, 1993 . Arctodus simus (Cope, 1879) from Riverside County, California . PaleoBios . 15 . 2 . 27–36.
7. Web site: 2010-09-24 . The Associated Press: Calif. utility stumbles on 1.4M-year-old fossils . 2024-07-23 . web.archive.org.
8. Web site: El Casco Substation . 2024-07-23 . LSA . en-US.
9. Web site: Southern California Edison Discovers Most Comprehensive Collection of Fossils of its Era in Southern California . 2024-07-23 . Edison International Newsroom . en.