34 



NEW YORK STATE MUSEUM 



bank lo rods from the mouth at 550 A. T. It is covered for some 

 distance up the ravine but occasional outcrops of the Moscow shale 

 show that it is nearly level to about 25 rods from the mouth above 

 which the strata rise rapidly toward the south and west for 35 rods 

 and then are nearly level for 15 rods to the falls where the lime- 

 stone crosses the ravine at 595 A. T. or 45 feet higher than at 

 the mouth. 



An exposure of Hamilton shale on the south side of Keuka out- 

 let half a mile above Dresden shows a strong dip toward the lake. 



Exposures in the south side of Perry point show a northeast dip 

 and the top of the Tully limestone is 120 feet higher in the Perry 

 point ravine than at a point directly east on the opposite side of 

 the lake. 



The apex of a fold crosses diagonally the ravine of Plum creek 

 ^ mile from the lake. On the east side of the fold the 

 strata descend toward the east at the rate of 150 feet or more 

 per mile. On the west side there is a slight western dip for about 

 half a mile when it is again reversed and is quite strong toward 

 the lake. At the Severn arch the top of the Tully is 45 feet above 

 the lake level but, on the opposite side it is below it, showing an 

 eastward dip of 20 feet or more per mile. 



At the south end of the lake the strata on the east side are 

 about 25 feet lower than on the west. Exposures are not favorable 

 to the measurement of dip on the east side in the southern part of 

 the quadrangle, but in the Lodi glen the Tully limestone shows a 

 western dip of 150 feet per mile, and the other ravines in this 

 vicinity show that this steep dip toward the lake continues for at 

 least 8 miles and that some of the apparent undulations of the 

 limestones are caused by sinuosities in the line of outcrop. A 

 western dip of more than 200 feet per mile is noticeable in the 

 quarries and roadside exposures in the western part of the village 

 of Ovid. 



On the east side of the ridge the eastward dip toward Cayuga lake 

 is shown in the ravines east of Hayt Corners and in the Big 

 Hollow creek and other ravines farther north. On the opposite 

 side of the lake conditions are much like those on Seneca lake, the 

 western dip being increased to many times the average. 



The diagram accompanying the map is designed to show highly 

 exaggerated the variations in the dip along the east and west line of 

 42° 40' across the Ovid and Genoa quadrangles, a distance of 26 

 miles. f 



