STATE GEOLOGIC MAP OP 1901 9 



some competent person be appointed to devote himself to that 

 'i- department. To this position Mr Conrad was assigned, thus 

 ' leaving a vacancy in the third geologic district, which, after a 

 reorganization of its boundaries, as before explained, was as- 

 signed to the charge of MrYanuxem,and Mr Hall was appointed 

 to the fourth district. 



During the five years of field work which . followed the 

 New York geologists accumulated a vast amount of mate- 

 rial and of facts regarding the geologic formations within 

 the state, proving conclusively that they could not be 

 parallel with any of the described and well determined 

 formations of Europe. The Silurian system of Murchi- 

 son, as described and illustrated in the Edinburgh Reiview, in 

 1838, and as finally published in 1839, though covering a portion 

 of similar ground, was not broad enough to meet the require- 

 ments of the geology of New York. Thus failing to find the 

 means of comparison and identification, the term ^' New York 

 system," was proposed, to embrace the sedimentary formations 

 from the Potsdam sandstone to the base of the Carboniferous 

 system; or, as the formations were developed in New York and 

 southerly into Pennsylvania, the upward extension of this term 

 reached to the base of the Coal Measures. This term " New 

 York system," included the formations ordinarily embraced by 

 the names Cambrian, Silurian and Devonian in England and on 

 the continent of Europe. 



In 1842 Mr Conrad resigned his position as paleontologist 

 of the survey without communicating any report to the gover- 

 nor; and the four geologists who had expected to avail them- 

 selves of the results of his investigations were left to their own 

 resources. In this state of affairs, each one of the geologists 

 illustrated his own report, as best he could, by figures of char- 

 acteristic fossils of the rocks and groups which he had studied 

 in his own district. By this means a very considerable num- 

 ber of the more common and characteristic fossils were illus- 

 trated in woodcuts, which were printed in tfie text, thus giving 

 authentic guides for the determination of all the more import- 

 ant members of the series. 



