April 3, 1876.] 261 |-price. 



abrupt, sometimes the rocks overhanging indicating that they are a portion 

 of an anticlinal. lb. 39. So our Appalachians and Atlantic seaboard liills 

 lean from the Atlantic Synclinal, as if the upheaving force was in the sink- 

 ing bed of that ocean, or as one preponderated in the balance the other 

 rose. 



One other great feature of structural geology is to be noticed in these 

 Reports. The mountains ai-e built of granite, gneiss, &c. From the Mis- 

 sissippi and Missouri to the Rocky Mountains the stratified deposits of 

 sandstones, limestones, shales, slates, and clays, lie in flat broad sheets, 

 "much as they were when first laid down, one after another in the bottom 

 of the vast ocean icMch once existed here. Since this ocean was gradually 

 drained off, the ceaseless action of the rains and rivers has in places re- 

 moved thousands of feet of these rocks, exposing beds which were once 

 deeply buried, and in which we can occasionally find the remains of shell- 

 covered beings which still earlier lived and died upon the ocean bottom, or 

 of the skeletons of the animals and plants which peopled the surrounding 

 shores, and were swept by the ancient rivers out into the sea to be buried 

 with the then forming sediments." Dr. Hayden's Report for 1873, p. 93. 



And Dr. Newberry, in the United States Report for 1870, says of the 

 lakes that once occupied the region immediately east of the Rocky Moun- 

 tains : " The sediments that accumulated in the bottoms of these old lakes 

 show that in the earliest periods of their history they contained salt water, 

 at least the sea had access to them, and their waters were more or less im- 

 pregnated with salt, so as to be inhabited by oysters and other marine or 

 estuary moUusks. "In due time the continental elevation which brought 

 all the country west of the Mississippi up out of the wide-spread cretaceous 

 sea, raised these lake basins altogether above the sea level, and surrounded 

 them with a broad expanse of dry land." p. 329. 



But how came such "continental elevation?" Not alone by lifting up 

 the continent bodily, else would the marine deposits have remained at the 

 top and the waters have been drained off, carrying off largely its deposits ; 

 but must have been largely raised up by the degradation of higher lands 

 or mountains by freezing, thawing, and erosions, and the flow of the ma- 

 terials into the basin of such sea and lakes, thus preserving both the salt 

 and the fresh water fossils found there in " wonderful " abundance. So 

 were Ohio, Indiana, and Illinois, filled and raised up, and hence, old river 

 bottoms are found far beneath the present surface. And the stratified 

 rocks thus formed have been since cut down into canons, and even the 

 granites also ; all disintegrated both by frosts, heats, and erosive waters, 

 and ice, as well as chiseled by "sand blasts." Hence are there many 

 rocks left perched in the west as in the east, that have never been lifted, or 

 floated by ice, but have simply held their positions after the surrounding 

 strata had been carried away by the above named dynamic causes. 



Dr. Newberry further testifies that, " In the progress of the Cretaceous 

 Age, the greater part of the continent west of the Mississippi sank beneath 

 the ocean, and the deposits made during the later portions of the Cretaceous 



