GEOLOGY OF SARATOGA SPRINGS AND VICINITY 9I 



basin and consist of Canajoharie, Schenectady and Indian Ladder 

 shales. Nor can the great thickness of shales, passed in well- 

 borings in the shale region itself, be considered as demonstrat- 

 ing a great thickness of the shales. In a well at Mechanicville, 

 for instance, 1400 feet of shale were passed without reaching the 

 bottom of the formation ; since the shales there, however, are not 

 only dipping at an average angle of about 70°, but also repeated 

 in overturned folds, the thickness of the shale in the well is clearly 

 no indication of a corresponding thickness of the shale beds. 



That the possibility exists of great thickness of these shales in 

 this region, however, is shown by the Canajoharie and Schenec- 

 tady shales in the closely adjoining basin to the west, which were 

 found to reach together more than 3000 feet in thickness. 



On the western side of Willard mountain there are exposed about 

 400 feet of grits, probably without repetition of the beds, a thick- 

 ness which fairly agrees with Dale's estimate. We would estimate 

 as follows : 



Grit 500+ feet 



White beds 400± feet 



Shale ioo±: feet 



Fauna of the Normanskill beds. Faunules, mainly of graptolites, 

 have been found in many places in the Normanskill belt on the 

 Schuylerville quadrangle. We cite here only the more important 

 occurrences which show the position of the grit, the white beds 

 and shales in the Normanskill formation. 



An outcrop of deep black shale, interbedded in the grit of the 

 Rocky tucks, about 2 miles north of Quaker Springs, contained : 



Corynoides gracilis Hopkinson 

 Didymograptus subtenuis (Hall) 

 Leptograptus sp. 

 Dicranograptus ramosus Hall 

 Climacograptus parvus Hall 

 C. scharenbergi Lapworth 

 Diplograptus cf. acutus Lapzvorth 



This is a typical Normanskill association of species. 



A six-foot bed of compact black cherty rock in a brook just 

 above Coveville contained : 



Dicranograptus ramosus Hall 

 Climacograptus parvus Hall 



