I have a couple of new fossils I need identified. By my guess they are Ammonites but what do I know? I'm fortunate that these snails come with some identification, a small piece of paper with some handwriting on it. From top to bottom, it says "Large Agate Snails, viviparous, miocene, Lahonten Formation, Black Rock Desert, Winnemucca, Nevada." I'm a little confused because from what I've read, Lake Lahonten did not exist during the Miocene epoch. The smaller snail is about 2½ cm (1") long, from top to bottom in the picture, and the larger snail is about 3 cm (1½") long. Is there anything anyone can tell me about these pieces? Those measurements don't include the concretion attached to them.