GEOLOGICAL SOCIETY. 



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tance of twenty or thirty miles over an open high 

 prairie, upon the west bank of the Missouri river, and 

 a few miles below its junction with the Yellow Stone, 

 near latitude 48°, these remains are most abundant. 



" The topography of this section of the country is 

 hilly, and much broken into deep ravines and hollows. 

 On the sides and summits of the hills, at an elevation of 

 several hundred feet above the present level of the ri- 

 ver and an estimated height of some thousand feet above 

 the ocean, the surface of the earth is literally covered 

 with stumps, roots and limbs of petrified trees, broken 

 and thrown down by some powerful convulsion of nature, 

 and scattered in all directions in innumerable fragments. 



" Some of the trees appear to have been broken off, 

 in falling, close to the root ; while others stand at an 

 elevation of some feet above the surface. Many of the 

 stumps are of large size ; I measured one, in company 

 with Dr. Gale of the United States' army, and found it 

 to be upwards of fifteen feet in circumference." 



The vegetable impressions observed in our coal mea- 

 sures are equally numerous and interesting as in any of 

 a similar nature in Europe, and all are of the same gene- 

 ral character with those obtained from the carbonifer- 

 ous and grauwacke series in Europe. 



Many of the fossil vegetables of our coal measures are 

 peculiar to America : such are, Neuropteris Cistii, 

 N. macrophylla, of Wilkesbarre, Pennsylvania; N. 

 Grangeri, of Zanesville, Ohio ; Sigillaria Cistii, S. 

 rugosa, S. Sillimani, S. obliqua, S. dubia, all from 

 Wilkesbarre, Pennsylvania; Lycopodites Sillimani, 



