PETROLEUM AND NATURAL GAS IN NEW YORK 489 



shaly, so that the dividing line between the two formations is 

 in many cases an arbitrary, one. A swing of several scores of 

 feet is possible in the fixing of these horizons as they are recog- 

 nized by different drillers. 



The best element in the series, that as to the position of which 

 there should be the least ambiguity, is the upper surface of the 

 Archaean granite. By its hardness it is so sharply contrasted 

 with all other formations that the driller always knows when 

 he has reached it, but there is a chance for discordant measure- 

 ments, and, as a matter of fact, many of the records are confused 

 and uncertain as to the depth at which the granite lies. Select- 

 ing a few records that are at least as good as the rest, we obtain 

 data which can be used in determining the problem of the dip. 



In central Jefferson county there is no doubt that the granite 

 lies about 900 feet below the surface. 



At Adams, it is given as 915 ft 



At Pulaski, Oswego county 1425 



At Parish " " . 2445 (?) 



At Central Square " " ' 2415 



At Stillwater, Orwell township 1697 



Several of these points are on an approximately north and 

 south line and the facts of the dip presented by them are shown 

 in the following tables. Distances are taken from maps and 

 from railroad measurements. 



The elevation of the surface necessarily comes into account. 

 The altitude of the points named below are herewith given. The 

 calculations were made on the true elevations, the differences of 

 surface altitudes having been first eliminated. 



Adams, r. r. station 599 ft above tide 



Pulaski, " 377 



Parish, well head . 474 



'Central Square, well head (399.9) 400 



Mexico, r. r. station 375 



Baldwinsville, " 390 



Warner, r. r. station 427 



Stillwater, " 900 



