178 Forty-sixth Report on the State Museum, 



Mr. Yanuxem, the latter, however, being willing to recognize a 

 series of conglomerates and crystalline rocks of St. Lawrence, 

 Lewis and Jefferson counties which were clearly below the 

 Potsdam sandstone as a distinct group worthy of recogni- 

 tion. The difficulty of the position and surroundings in being- 

 compelled to decide questions when the facts were not of 

 common knowledge to the four geologists, rendered the situation 

 embarrassing ; and without the time and means for the staff to 

 visit and review the doubtful or disputed points there seemed no 

 other course left but to sanction the map as published. At this 

 distance of time and with the accumulated knowledge coming 

 from all sides, it is easy to criticise the work done upon the geo- 

 logical map published sixty years ago. This map, however, has 

 served as the basis for later work ; and supplemented as it was 

 in 1843 by a geological map of the Middle and Western States, 

 published in the Report of the Fourth District, we have had a 

 fairly good basis for work among the Silurian and Devonian 

 rocks of JSTew York and of the States west to the Mississippi 

 valley. This map of 1843 presented the first attempt at a 

 correlation of the rocks of New York, and the east, with those 

 of the west ; traced through a thousand miles in extent 

 by their fossil contents, at a time when not a tithe of these 

 fossils had received names, and most of them were entirely 

 unknown in scientific literature or nomenclature. It was an 

 attempt also to carry the nomenclature of the New York system 

 of rocks into the western States, which later investigations in the 

 same direction, have rendered acceptable, and which have become 

 established in the literature of the geological reports of all these 

 States. Crude and imperfect as such a map must necessarily 

 have been, complied from all sources within reach, not always 

 fully authentic ; supplemented and verified b}^ some thousands of 

 miles of travel, it has nevertheless, by the testimony of impartial 

 authority served a very useful purpose to the geologists of later 

 years. Nearly sixty years have passed since its publication, its 

 errors have been pointed out sometimes with acerbity-, but almost 

 universally treated with leniency, and the map with commen- 

 dation, as having served a useful purpose in the infancy of our 

 investigations in the Palaeozoic rocks of North America. 



When placed in charge of the work of the Paaelontology of 

 the State in 1843, it was natural that I should desire to rectify 



