Professor Marsh in the '705. There is no reason why any American or foreign museum should 

 be without these, the very choicest of all museum specimens. 



" Besides the fossils mentioned there are about one hundred species of invertebrates to 

 collect, then species of fishes and turtles, and a number of species of extremely rare cycads. 



" The Cretaceous rocks cover about one-half of the State, and have a maximum thickness 

 of about 20,000 feet. They are also rich in fossil life, but they are not as well known as the 

 Jurassic, for they have not received the attention from scientific men. In fossil plants they 

 abound, and in case the fossil flora of the Tertiary is included with the Cretaceous, there are 

 300 species described, and no doubt as many more to discover, that are found in the Cretaceous 

 and Tertiary of other districts, or that are new to science. 



"The invertebrate fossil life contains hundreds of species in fact, all of the Cretaceous 

 species common to the Rocky Mountain region. They are so plentiful that one can often, in 

 a single day, collect 100 species. The vertebrate fossils are also very important, and there are 

 many families and orders represented. The huge Dinosaurs, so common in the Jurassic period, 

 lived also through the Cretaceous, but they were not so abundant, nor did they, as a rule, grow 

 as large. Not over a half-dozen species have been reported from the Wyoming Cretaceous, 

 but with careful and painstaking labor very many more may be discovered. 



" Swimming Saurians were also very numerous, but only a few have been reported. The 

 number will no doubt approximate the Kansas fauna when the series are better known. 

 The remains of the fishes should also be mentioned, for there are many species of shark 

 and similar animals. 



" The Tertiary is a very extensive formation, and is represented by many groups, which 

 occupy some of the valleys, such as the Big Horn Basin, Wind River, Green River, Sweetwater 



27 



