402 APPENDIX E. — GEOLOGY. 



The route from the Missouri westward shows a continuation of 

 this limestone as far as the Big Blue. 



Here it disappears, judging from specimens and remarks in the 

 notes. It is soon succeeded by strata of cretaceous age, which, 

 from the specimens preserved, I have been able to recognise as 

 extending for a considerable distance on the route between Turkey 

 Creek and Big Sandy. 



Among the cretaceous fossils are a species of PTioladomya^ and 

 the Inoceramus^ which is so common and abundant in numerous 

 localities in this region. 



It is quite probable that these beds extend much farther, but 

 I find no specimens in the collection; and the notes indicate that 

 there are heavy deposites of drift, which may have obscured the 

 exposure of the formation below. 



This drift formation, (judging from the descriptions given in the 

 notes,) or the debris from the immediate geological formation, ap- 

 pears to have covered the older stratified deposites, since no men- 

 tion is made of them till approaching the forks of Platte River on 

 the 25th June. At this point were collected some specimens of 

 clays with small marine shells, too imperfect for determination; but 

 from the general character, and from the occurrence of bones in the 

 same place, it is presumed that they are of tertiary age. Above 

 the forks of the Platte River similar bones and shells are noticed, 

 and, on the 1st of July, specimens of bones were collected. Nu- 

 merous fragments of bones were collected on the 3d of July, ap- 

 parently belonging to some mammalia of the herbivorous character. 

 These bones are too imperfect for determination beyond their 

 general character. From the description of the mode of occurrence, 

 and their being imbedded in a matrix of considerable hardness and 

 tenacity, one would be led to infer that they were of some tertiary 

 deposite. 



Among these specimens is a single ramus of the lower jaw, which 

 apparently belonged to some carnivorous animal ; but no teeth are 

 preserved in it, nor were any teeth of any kind found in the col- 

 lection. 



From July 3d to 11th, the notes give no evidence of any thing 

 of special interest. On the latter date, bones are mentioned as 

 occurring in the locality examined, but no specimens having this 

 date are preserved in the collection. 



It would appear that the character of the country from near 

 Fort Kearny to near Fort Laramie is uniform, and that no de- 



