Pleistocene-Holocene Frags

[RFausta]

I know this is quite a long shot but the pores/foramen are just KILLING ME, the shape is so familiar, but I just CANNOT drag it out of my brain. 

Location: Southern California, Mojave Desert. Quaternary alluvium/older alluvium (depth 8 ft) in an area where mammoths and camelids have been found (3 miles northwest, 5 feet below surface). Pleistocene dry lakes lie just to the east. The bones are at least somewhat mineralized, but obviously have a pretty high level of preservation. 

Pictured are two separate bones with very distinct shapes/pores/etc. No bones have anything particularly diagnostic nor any obvious processes etc.