STATE GEOLOGIC MAP OP 1901 13" 



thus found to be complete and the positions of its members^ 

 well established. Subsequently the positions and boundaries of 

 these members have been located in detail throughout the south- 

 eastern counties by the writer and his assistants, Messrs Blake, 

 Ries, Newland, Hill and Eckel. 



The rocks of the Taconic range and adjoining areas 

 Most of the so called " Taconic " rocks fell, on the first geolog- 

 ical survey of the state, within the district assigned to Mather,, 

 who appears to have recognized their true character and rela- 

 tionship. Emmons, however, insisted that they formed a sepa- 

 rate and distinct system underlying the Silurian, and his views- 

 were accepted, under protest, by Mather in his final report. 

 Owing to the later advocacy of Emmons's views by Hunt and 

 Marcou, neither of whom performed any field work in the region, 

 the " Taconic question " left a marked impression on the litera- 

 ture of New York and New England geology. The subsequent 

 work of Dana and Walcott was, however, decisive, and since 

 then the only problem has been the exact correlation, so far 

 as exactness is possible, of these Taconic rocks with the unmeta- 

 morphosed strata of the Cambrian and Silurian formations. 



So far as the area covered by Dale in his work on the slate 

 belt falls within the limits of the 1901 map, his boundaries and 

 correlations have been followed. Maps from several of his 

 other papers have been used for smaller areas, while some areas 

 on the eastern border are taken from the maps of Pumpelly and 

 Emerson. Dwight's manuscript maps contributed for the occa- 

 sion have been followed for most of Dutchess county, north of 

 the Highlands. 



With the exception of small areas near Lake Champlain, 

 credited to Brainerd and Seely, the remaining part of the Paleo- 

 zoic mapped east of the Hudson is from the work of Dana and 

 Walcott. Dana's mapping covers a relatively small area in 

 northeastern Dutchess and southeastern Columbia county and 

 in the adjoining portions of Massachusetts and Connecticut; 

 while Walcott's boundaries have been followed for most of Rens- 

 selaer and Washington counties and nearly all that part of 

 Vermont which appears on the map of 1901. 



