GEOLOGY OF OLD HAMPSHIRE COUNTY, MASSAl^HUSETTS, COM- 

 PRISING FRANKLIN, HAMPSHIRE, AND HAMPDEN COUNTIES. 



By Benjamin Kendall Emerson, 



Professor ok Geology in Amherst College. 



CHAPTERI. 



INTRODUCTION. 



AREA COVERED. 



Old Hampshire County, which formerly stretched across the State of 

 Massachusetts between Berkshire on the west and Worcester on the east, 

 has been less fortunate than these and has lost Franklin County on the 

 north and Hampden on the south. Amherst lies in the center of this area, 

 and hence it has come about that for many years the region has been 

 the field of my geological studies. 



The rocks strike north and south and run quite across New England 

 and beyond, so some artificial limits had to be chosen in these directions, 

 and the limits of the State were as convenient as any. On the east and 

 west, the area lying between the plateau of Worcester County on the east 

 and the full development of the Berkshire Hills country on the west pos- 

 sesses a good degree of geological unity, the Cambrian gneiss of its eastern 

 and western boundaries being almost certainly continuous beneath the whole 

 area and supporting several series of schistose rocks, which culminate in the 

 Bernardston highly metamorphosed but fossiliferous beds of Devonian age. 

 The area includes, also, the northern half of the Triassic ten-ane, which 

 reaches nearly to the north line of the State, while the sudden Avidening of 

 the valley of the Connecticut just at this northern point, with the lowering 



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