APPENDIX E. 



GEOLOGY AND PALJEONTOLOGT. 



BY PROF. JAS. HALL. 



Albany, February, 1852. 



Captain Stansbury: 



Dear Sir : — I have examined with care the specimens of rocks 

 and fossils which you submitted to my inspection. I find them, 

 with some few exceptions, to represent very clearly the products 

 of four distinct geological periods, as follows : — The older are me- 

 tamorphic rocks of silurian or devonian age, or perhaps both; the 

 next in order, and recognisable by their fossil remains, are of the 

 carboniferous period ; the third are of the cretaceous period ; and the 

 fourth are of the tertiary. Besides these there are the products 

 of ancient volcanic action in the basalts and amygdaloids, with 

 some specimens of obsidian. 



After a careful examination of the specimens, and a comparison 

 with the notes and journal which you submitted to me, I have 

 marked upon the map of your route, and upon the map of the 

 Salt Lake region, the different colours indicating the -character 

 of the geology at the different points where the specimens were 

 collected. I am aware that the specimens with the notes, together, 

 would have warranted me in colouring in a more extended manner, 

 but I have preferred to confine myself to the position and actual 

 evidences furnished by specimens. By having the map in this 

 condition nothing is hazarded, and every new fact obtained can be 

 readily added to it, or it may be filled up to some extent from the 

 indications furnished by the topographical features. 



It will be the more satisfactory mode to follow your route in the 

 remarks I shall make in this connection. 



The firsi specimens furnished are from the west side of the Mis- 

 souri River, near and above Fort Leavenworth. These are all 

 from limestone of the carboniferous period, and apparently from 

 the upper of the two great limestones of this period in the west. 

 The most conspicuous fossils are Productus, Terebratula, &c. 



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