San Timoteo Formation


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.

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.

Fossils

Fossils of Irvingtonian prehistoric mammals were found in the San Timoteo Formation. These include:
  • Canis edwardii
  • Microtus sp.
  • Ondatra idahoensis
  • Mictomys kansasensis
  • Erethizon cascoensis
  • “Plesippus” fracescana
  • Equus bautistensis
  • Tapirus merriami
  • Odocoileus cascaensis
  • Megalonyx sp.
  • Mammuthus sp.
  • Possibly a giant bear
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.