No. 4.] HUNT — ON CAMBRIAN AND SILURIAN. 417 



HISTORY OF THE NAMES CAMBRIAN AND 

 SILURIAN IN GEOLOGY. 



By T. Sterry Hunt, LL.D., F.R.S. 

 (^Concluded from page 312). 



III. Cambrian and Silurian Rocks in North America. 



In accordance with our plan we now proceed to sketch the his- 

 tory of the lower paleozoic rocks in North America. While 

 European geologists were carrying out the researches which have 

 been described in the first and second parts of this paper, Ame- 

 rican investigators were not idle. The geological studies of Eaton 

 led the way to a systematic survey of the state of New York, the 

 results of which have been the basis of most of the subsequent 

 geological work in eastern North America, and which was begun 

 by legislative enactment in 1836. The state was divided into 

 four districts, the work of examining and finally reporting upon 

 which was committed to as many geologists. The first or south- 

 eastern district was undertaken by Mather, the second or north- 

 eastern by Emmons, the third or central by Vanuxem, and the 

 fourth or western by James Hall ; the paleontology of the whole 

 being left to Conrad, and the mineralogy to Beck. After various 

 annual reports the final results of the survey appeared in 1842. 

 The whole series of fossiliferous rocks known, from the basal or 

 Potsdam sandstone to the coal-formation, was then described as 

 the New York system. 



At that time the published researches of British geologists 

 furnished the means of comparison between the organic remains 

 found in the rocks of New York, and those then known to exist 

 in the paleozoic strata of Great Britain. Prof. Hall was thus 

 enabled in his Geology of the Fourth District of New York, to 

 declare, from the study of its fossils, that the New York system 

 included the Devonian of Phillips, the Silurian of Murchison, 

 and the Cambrian of Sedgwick ; meaning by the latter the Upper 

 Cambrian, or Bala group, which alone was then known to be fossi- 

 liferous. From the evidence then before him, he concluded that 

 the Upper Cambrian was represented in the New York system 



Vol. VI. T . No. 4. 



