| Fossil freshwater pelecypods, genus Pisidium sp. from the Upper Pleistocene Sehoo Formation, Nevada; specimens are roughly 20,000 years old. Size of specimens, left to right: 15mm, 13mm, 15mm across. |
| Fossil freshwater pelecypods, genus Pisidium sp. from the Upper Pleistocene Sehoo Formation, Nevada; specimens are roughly 20,000 years old. Size of specimens, left to right: 15mm, 13mm, 15mm across. |