AMERICAN GEOLOGY DECADE OF 1850-1859. 4()1 



which were referred to Messrs. Hall and Conrad for determination and 

 report. The published report, the work of all the above mentioned, 

 comprised but 174 pages of text, with 21 plates of fossils. It was, 

 however, noteworthy in containing a colored geological map of the 

 Mississippi Valley and country to the west. This has the distinction 

 of being the earliest colored geological map of the region published by 

 the Government. It is, moreover, of historical interest as showing 

 how little was definitely known of the region. The known mountain 

 ranges were colored as metamorphic, often flanked by more or less 

 sinuous, narrow bands of Cretaceous and Carboniferous rocks. Large 

 areas of igneous- rocks were represented as occurring in the extreme 

 northwest (California, Oregon, and Washington), but the great inte- 

 rior, the Great Basin region, was left almost entirely blank — geolog- 

 ically a terra incognita. 



The fossils, collected largely from Texas, were almost wholly Ter- 

 tiary, Cretaceous, and Upper Carboniferous forms. A few Lower 

 Silurian forms were figured and named b} T Hall, but no descriptions 

 were given. 



What should have been the most important work on economic 

 geology of the year, and perhaps the most important thus far to 

 appear, with the exception of Whitney's Metallic Wealth of the United 



States, already noted, was Lesley's Manual of Coal 

 coai? y i856. anua, ° f aQ d ^s Topography, issued in 1856 — an octavo volume 



of 224 pages. The scope of the volume was, however, 

 scarcely what one would be led to expect from its title, and its possible 

 usefulness sadly marred by the personal claims of the author. Not 

 confining himself to the subject of coal and its topography, he entered 

 freely into the subject of mountain structure, with especial reference 

 to the Appalachians, the formation of \ alleys, theories of the drift, 

 topographical drawing, and kindred subjects. Lesley was, it should 

 be remembered, a topographical assistant on the survey under Rogers 

 in 1839-1851. Reference to his work while on the survey is there- 

 fore to be expected, though it must be confessed one's expectations 

 are somewhat exceeded when he lays claim, on his own behalf and 

 that of Messrs. Whelpley and Henderson — also assistants on the 

 Rogers survey — to having been the first to unravel the intricacies of 

 Appalachian structure. " Years of patient toil," he writes, " it cost 

 us to unfold the mysteries of the Pennsylvania and Virginia range." 

 This same claim, in an even more aggressive form, he put forward 

 again three years later, in his Iron Manufacturer's Guide, which 

 appeared under the authority of the American Iron Association, of 

 which he was secretary, in 1859. a 



"These attacks brought forth an emphatic rejoinder from R. E. Rogers (a brother 

 of H. D. Rogers), which was printed privately in form of a pamphlet of 22 pages, 

 1859. 



