FIFTH REPORT OF THE DIRECTOR I908 121 



ant was that by James Hall, a Geological Map of the Middle and 

 Western States, which has had a powerful influence on the geol- 

 ogy of eastern United States. This hand-colored map indicates 

 the phenomenal advance made in stratigraphy since the publication 

 of Eaton's map of the State 12 years before, and Hall's map 

 appears with divisions, a number of which have remained almost 

 as set down, to the present day. In the interval between the 

 two maps, Murchison and Sedgwick in Great Britain had carried 

 on their stratigraphic studies clearing up or even beginning a real 

 classification of sedimentary strata. The efforts of these men were 

 felt in America, and Xew York State forged its way to the front 

 under the leadership of James Hall, who in turn was guided by 

 the overruling persuasion of Murchison. 



Accompanying these reports and published separately was also 

 the famous " 1842 " map of the State Geologists. Previous to its 

 appearance all geologic mapping had been greatly hampered by a 

 lack of accurate base maps on which to indicate the geological 

 formations. Therefore the State had a special map engraved for use 

 by the survey and this was used in the 1842 map. This was hand- 

 colored, prepared by the four geologists, Emmons, Hall, Yanuxem 

 and Mather. They had been obliged to create what was called the 

 " Xew York system " of rocks including the strata from the Pots- 

 dam to the Carboniferous, as they were as yet unable to correlate 

 the various strata with Murchison's Cambrian, Silurian and De- 

 vonian. The central mass of the Adirondacks was all colored as 

 Primary. 



Dr Emmons's views in regard to the Taconic system were at 

 variance with those of other geologists and later (1844) he pre- 

 pared a map on the same base as the former one, but having his 

 Taconic system upon it. This has been called the " Emmons map." 

 It was, however, never widely distributed. The 1842 map, as Pro- 

 fessor Marcou says, 1 marked " a second starting point in American 

 geology " and adds that it gave a good classification of the Ameri- 

 can paleozoic rocks due mainly to the researches of Emmons and 

 Yanuxem, an unjust comment due to his personal dislike to Pro- 

 fessor Hall, and giving him but scant credit for his important share 

 in the work. 



The next published maps were those of Sir Charles Lyell accom- 

 panying his North American travels. They dealt with western 

 New York, but included one United States map, the New York 



*U. S. Geol. Sur. Bui. 7. 1884. P- 59- 



