AMERICAN GEOLOGY — DECADE OF 1840-1849. 369 



From paleontological evidence Conrad was led to consider the lime- 

 stone of the Savannah River in Georgia between Savannah and Shell 

 Blurt' as Upper Eocene, and thought that very probably the prevailing 

 limestone of Florida would be included in this division. He also found 

 evidence to lead him to believe that a considerable post-Pliocene 

 elevation of the whole Florida peninsula had taken place, and that the 

 Florida keys were a product of this movement. 



At the fourth annual meeting- of the Association of American Geol- 

 ogists and Naturalists D. D. Owen read ;i paper on the geology of 

 the Western States, including under this designation the region of the 

 Ohio Valley. Abstracts of this paper appeared in the 

 ai^oTthe the American Journal of Science for 1843. At the Novem- 

 wes_tern states, k er (1^42) meeting of the Geological Society of Lon- 

 don Mr. Lyell presented for Doctor Owen the same 

 paper, which was afterwards published in the journal of that society 

 under date of 1846. It seems proper, therefore, that this paper 

 should receive consideration here, particularly since Owen attempted 

 a correlation of the American rocks with those from Europe. As 

 published, the paper was accompanied by a colored geological map 



4 



Fig 32. — General section across the Western states. (After i>. i>. Owen.) 5, diluvium; l, marl and 

 greensand, probably cretaceous; 3, bituminous coal formation; J, carboniferous limestone of 

 Europe; 1. probable equivalents of the Silurian rocks. 



of the Ohio Valley and the generalized section shown in fig. 32. The 

 attempts at correlation, it should be noted, were founded on paleon- 

 tological data. The limestones immediately underlying the coal (3 of 

 the section) he considered to be the equivalent of the European Carbon- 

 iferous. These rested upon a series of rocks, the upper one hundred 

 feet of which Hall had assigned to the Devonian. The middle and 

 lower beds Owen regarded as the equivalent of the English Upper 

 Ludlow, as defined by Alurchison. Below this he found shales which 

 he believed to be equivalent to the English Low T er Ludlow and the 

 New York Marcellus shale. The shale-bearing rock he regarded as 

 the equivalent of the Wenlock formation of Murchison. 



The fundamental rocks of the Ohio Valley he considered as the 

 equivalents of Murchison's Lower Silurian, the lower 75 to 100 feet 

 corresponding to the Llandeilo flags and the rest to the Caradoc sand- 

 stones. The corresponding formations of New York appeared to be the 

 Trenton limestone and shale, representing the older series, and the 

 Salmon River and Pulaski sandstone, the rest. 



Perhaps the most important outcome of the geological surveys of 

 Pennsylvania and Virginia and certainly, from a strictly scientific 



NAT MUS 1904 24 



