STATE GEOLOGIC MAP OP 1901 17 



EARLIER GEOLOGIC 3IAPS AND THEIR GEOGRAPHIC BASES 



The maps of 1842 and 1844 



The condition of the geographic maps of New York in 1812 



can best be shown by quoting the words of Prof. Hall.^ 



Upon the organization of the Geological Survey of the State of 

 New York, one of the first objects sought was a map for laying 

 down the limits of the geological formations. At that time there 

 were no accurate maps except of small parts of country, and the 

 l)est resource was found in Burr's atlas of the state and county 

 maps of the State of New York. There seems to have been no 

 approximately correct geographic map of the state available for 

 the use of the geologists in recording their observations. At 

 the close of the survey a small map was engraved expressly 

 for the use of the geologists in laying down the limits of the 

 geological formations. This map from the eastern limits of 

 the state adjoining Massachusetts, Connecticut and Vermont 

 to its western extremity was about 28 inches, and its extreme 

 limit from north to south along the eastern counties of the state 

 or from the Canada line to Sandy Hook was 2 inches less than 

 its extent from east to west, or 26 inches. The locations of 

 towns, villages and postofQces were doubtless taken from the 

 best maps extant, but these afforded very unsafe guides for 

 locating the outcrops of the geological formations. 



Emmons's map of 1844 was colored on the same base as the 

 map of 1842. 



In 1867 a geologic map of Canada and the northern and east- 

 ern United States was published by Sir William Logan, director 

 of the Canadian Geological Survey. This map is on a scale of 

 25 miles to the inch, and is of interest in the present connection 

 because of the fact that the geology of the United States was 

 compiled for it by Prof. Hall. The geologic mapping of New 

 York there shown is, therefore, the first authoritative revision 

 of the 1842 geologic map of New York. 



Of this map it is said that only three copies were sent to the 

 United States. These were presented to Prof. James Hall, Prof. 

 James D. Dana and the United States Coast Survey. A repro- 

 duction on the scale of 125 miles to the inch is contained in the 

 atlas accompanying the report of progress of the Canadian 



Geological Survey for 1863. 



^N. Y. state Geol. 12th An. Rep't. 1893. p. 27. 



