Worldwide, easily the most common fossils are from marine invertebrates. Most sedimentary rocks are formed in the ocean, invertebrates are present in vast numbers, and the ocean is an excellent place to be buried in the mud, increasing the likelihood of being preserved. In contrast, the fossil collections at the Western Science Center are dominated by terrestrial deposits from Riverside County, so most of our fossils are land vertebrates. We do, however, have a pretty good collection of terrestrial and freshwater invertebrates in the collections.
Above is the shell of an amber snail (Gastropoda) from the genus Succinea. Amber snails are air-breathing snails (they have lungs) that generally live in marshy areas. The genus is wide-ranging, and modern Succinea are found all over North America. Below is the same shell in a different orientation, showing the aperture (the opening to the inside of the shell):
Succinea is a tiny snail; the black box the shell is sitting on in the images is only 1 cm across! A fairly large number of Succinea shells were recovered in the Pleistocene deposits from Diamond Valley Lake.