20 NEW YORK STATE MUSEUM 



Hopewell Junction and three somewhat larger ones east of 

 Pleasant Valley. All appear to be brought up by faults within 

 the slates. Several are marked by a limestone conglomerate 

 entirely similar to the Trenton conglomerate of the Wappinger 

 creek belt and Solenopora com pacta was noted in the 

 most western masses. These patches are now exposed because 

 of greater thrust at the points where they now lie along extensive 

 thrust lines. The conglomerate is often overlain by a silicious 

 lime-sand rock which is followed by the slate formation. As 

 far as it goes the evidence would appear to show that at the 

 east the lime-mud rock with fossils shown at Pleasant Valley, 

 Rochdale and at Sleight's farm near Manchester Bridge gives 

 way to this coarser silicious sand rock. Close folding and prob- 

 able thrusting have brought these two phases of contemporaneous 

 deposition into closer areal relations than they had originally. 



It seems likely that the epoch of limestone formation during 

 the Trenton transgression within this quadrangle was of short 

 duration. Much of the slate is probably of Trenton age. 



Surficial geology 



Some reference has already been made to these features in 

 Saratoga county and additional work was done on the general 

 field of the lower Mohawk valley region over the Broadalbin, 

 Gloversville, Amsterdam and Fonda quadrangles by Professor 

 Brigham. This continued field work has brought to an essential 

 completion the classification and distribution of the surface 

 deposits in this region and the necessary maps and report have 

 been rendered. Extension of this survey was carried into' the 

 area north of Gloversville, a district belonging to the southern 

 Adirondack forest and lying in the towns of Mayfield, Bleecker 

 and Garoga in Fulton county, and including the southern parts 

 of Benson and Arietta in Herkimer county. 



The region is rugged, in large part wooded and attains a maxi- 

 mum altitude in Pinnacle mountain, of 2514 feet. Many other 

 elevations approximate this altitude. The valleys and slopes are 

 covered with a massive and fairly constant mantle of glacial 

 drift. Rock outcrops are frequent, but the average thickness 

 of the drift is large. Distinctly morainic accumulations are, 

 however, not important though some low hills of this nature 

 occur about Bleecker, Bleecker Center and Lindsley Corners. Lakes 

 and ponds are numerous, and belong in the main to the glacial 

 blockade type, though it would often be hazardous to affirm that 

 glacial erosion did not enter as a component factor. 



