GEOLOGY. 291 



spring it was all mud, and in the summer the clay cracked so as to draw out 

 the roots of vegetation and destroy it. Along the bottoms was occasionally 

 a little good soil, but it was not valuable. This clayey soil was dark, but not 

 with organic matter. He had seen in Mr. Meeks's notes that night after 

 night he was compelled to camp with bitter water, and send out the men to 

 gather a few stunted willows or cotton- wood for fire. Most of the water was 

 impregnated with saline materials ; and, as all the water in the Mauvaise 

 Terres contained sulphate of magnesia, the party were compelled to submit 

 to its medicinal effects. Southward, toward the Platte was some better land, 

 but little wood. Kansas was much like Nebraska, and the climate was such, 

 that in a great part ol the territory it would be difficult for New-England men 

 to exist. He knew that Nebraska was a desert, and would remain so for all 

 time to come. [This curse of barrenness does not apply to the settled por- 

 tions of Kansas. They are carboniferous.] 



Professor Agassiz said that this was very important to us as presenting for 

 the first time the subdivisions of the cretaceous. His friend had omitted hi his 

 account of early explorers, the Prince of Neuwied, who in his travels col- 

 lected cretaceous fossils, and went back to Europe and gave us for the first 

 time the information that there were cretaceous fossils there. Several of them 

 were published, and one species, the mosasaurus, had not been rediscovered. 

 Now it was evident that these cretaceous deposits were not one and the same, 

 but formed a succession of deposits which contained different fossils. Now hi 

 Europe the whole series of cretaceous formations had lately been subdivided 

 into a number of subdivisions, and although he agreed completely with the 

 doctrine laid down by the chairman (Professor Dana), that we should not com- 

 pare our formations servilely to those of Europe, yet the deposition of the 

 whole cretaceous series hi Europe and in America were in the main syn- 

 chronic. He believed that the specimens of Professor Hah 1 , limited as they 

 were, afforded in themselves sufficient evidence thai the cretaceous deposits 

 hi Nebraska corresponded to the upper strata of the cretaceous hi Europe. 

 He had not yet seen a single entire fish-scale, only drawings of fragments of 

 scales, but he was sure that the upper beds were the equivalents of the En- 

 glish white chalk. 



Mr. Hall then spoke on the geology of ths Rocky Mountains. He said 

 that his knowledge of the Rocky Mountains was derived from specimens 

 brought by Fremont and Emory. All the specimens from the metamorphic 

 regions, whether from the north or south, had one character, and there was a 

 large proportion of red feldspathic granite associated with other rocks. Their 

 age he could not determine. After leaving the mouth of the Platte nothing 

 but the cretaceous and tertiary were to be found until one reached the head 

 waters of the rivers flowing eastward, the cretaceous came out again from 

 beneath the tertiary. He had not yet learned of cretaceous fossils being found 

 west of the Rocky Mountains. Beyond this was the carboniferous limestone 

 belonging above the coal-bearing beds. It generally rested on metamorphic 

 rocks, which formed the bases of the mountains. There were none of the 

 mica and talcose slates so frequent hi the Appalachian. The elevation of the 

 Rocky Mountains was post-cretaceous, the cretaceous beds being uplifted with 



