GEOLOGY GALLERY Rocks, fossils, and rubbings See volcanic rocks from a million years ago when eruptions of volcanoes were a regular happening.   Examine glistening barite crystals in many forms and colors.   Marvel at casts made from the actual fossils of three Ice Age mammals which are now extinct.     Take a look at the first dinosaur fossils found in southern Nevada. Discover exactly how big the state fossil ichthyosaur really is.        WHO AM I? The state fossil ichthyosaur, Shonisaurus popularis, is 48 feet long and 225 million years old, a few million years older than the dinosaurs.  Ichthyosaur fossils have been found throughout the world and come in all sizes.  Several species have been found in Nevada but Shonisaurus is the most largest and once was the largest in the world.  One of its relatives, 75 foot long  and only 205 million years old, was found in Canada in 1990.  Some of Shonisuarus' fossil "bones" are on exhibit in front of the 48 foot carved relief of this state symbol.  Others of this species can be seen still in the earth and rock at Berlin-Ichthyosaur State Park. Make a RUBBING of the ichthyosaur, the horse, the mammoth and the ground sloth in this gallery. The Pacific Horse, an ancestor of today's horses, did live in Nevada but became extinct some time during the last fifteen thousand years.  The horse began life on what is now the North American continent as a small dog size animal some time between 38 and 54 million years ago.  The horse which looked like today's horses traveled to Asia around 10 million years ago, long before it disappeared from North America.   Horses returned to their homeland here when the Spanish brought them across the ocean by ship in the 1500s.