Large Fossil 13lb - 8" Bone Section in Soft Stone California Nevada Paleontology

Description

This has been in my family for at least 35 years found on one of the properties. Either in the San Francisco Bay Area or Reno Nevada. It used to be in one piece but has naturally cracked apart into 4 pieces due to sitting exposed to elements outside. Is now stored inside since it cracked for several years now.
Entire specimen including bone section is 14" x 7.5" x 4.75" weighing about 13 lbs
Bone section is approximately 8" long x 3" wide
See photo for actual item. Please message if you have any questions. Thanks for looking!