GEOLOGY OF THE BROADALBIN QUADRANGLE 3/ 



On the geologic map the only Canajoharie shale area extends 

 from North Broadalbin westward to the vicinity of Munsonville 

 and thence southward to the map corner and represents the north- 

 eastern extension of the great shale area around Amsterdam and 

 Gloversville. South of Vail Mills and in the vicinity of Munsonville 

 no outcrops occur because of heavy drift covering, but the presence 

 of underlying shale is proved by the numerous shale fragments in 

 the drift. 



Good exposures have been found in the creek just east of May- 

 field station ; on Kennyetto creek one mile west, one mile north- 

 west, and two miles north of Broadalbin ; three miles west-southwest 

 of Broadalbin; at the lower road crossing on Beaver creek; and 

 in the creek just west of North Broadalbin. A mile south of North 

 Broadalbin the Canajoharie and Trenton are almost in contact but 

 the exposures are poor. Along Kennyetto creek, west of Broadal- 

 bin, the shale beds are strongly disturbed and show dips up to 25 

 or 30 degrees in varying directions. This disturbance is doubtless 

 due to proximity to the Broadalbin fault. 



Nothing like a complete section occurs within the quadrangle 

 so that the thickness of the formation can not be accurately deter- 

 mined. The summit is nowhere present, but judging by the dip 

 and relation to the other formations there are probably at least 

 one hundred feet of the shales here. 



Graptolites are common near the base of the formation, especially 

 along the creek just east of Mayfield station. 



UTICA SHALE 



The one small area of Utica shale is shown near the southeast 

 corner of the geologic map. Lithologically the Canajoharie and 

 Utica shales are indistinguishable but the recent work of Doctor 

 Ruedemann shows an important faunal distinction based largely 

 upon the graptolites. The thickness of the Utica, within the map 

 limits, can not be determined because only the upper portion is 

 present and this is practically in contact with the overlying Frank- 

 fort. The small area of the map is merely a tongue of the great 

 shale area extending for miles eastward. Good exposures occur 

 along the small creek a mile east of Galway. The shale mass here 

 lies against Galway fault no. 1 and close to the fault the strata 

 dip from 25 ° to 30 southeastward and away from the fault duo 

 to the updrag as a result of the displacement. 



