186 GEOLOGY OF OLD HAMPSHIEE COUNTY, MASS. 



THE WHETSTONE-SCHIST. 



This rock is a fine but very even- and sharp-grained, almost massive 

 sandstone, with small scales of a deejj-brown biotite, notched and irregular, 

 and often inclosing grains of the quartz scattered distantly but very regu- 

 larly in it. The biotite was of course formed where it now is, but the 

 quartz grains seem to be j^i'etty purely clastic. 



It occurs in distinct beds in the mica-schist, often of considerable 

 thickness — 33 to 262 feet. It generally grades into the mica-schist by 

 increase of the size and change in the position of the biotite, and often by 

 the appearance of garnet and staurolite. 



It occm's most abundantly in Chestei-field and Worthington, where the 

 beds run for long distances with the strike, and where I spent much time in 

 tracing them out, hoping to get useful material for the study of the struct- 

 ure of the mica-schist. I have put them down on the map just as I found 

 them, letting them end where the outcrop ends, and not generally connecting 

 fragments unless it was quite certain they were continuous. In many cases 

 one can see on the map that disconnected portions are probably continuous. 

 In many cases the common schists were found after an interval in exact 

 continuation of the whetstone. In a few cases this could be proved to be 

 caused by small faults; farther north in Franklin County and east in the 

 granitic area these beds are less distinct or wanting, with one notable excep- 

 tion detailed below. 



The rock culled whetstone in this section is not, of course, everywhere 

 suitable for whetstones, though portions of the beds may be of the right 

 textm-e for this purpose ; indeed, these beds have been quarried for whet- 

 stone for many years. Good quarries are found on the south slopes of tlie 

 spodumene hill in Huntington; the best at B. Shaw's in Cummington. 

 They are called Quiimebaug stones, and I was interested to find them 

 selling for 50 cents apiece, as the best stones obtainable, at a hardware 

 store in Brattleboro, Vermont. 



Oflicers of the Pike Manufacturing Company, which owns quarries in 

 Cummington and which controls the manufacture for a large part of New 

 England, state that the founder of their business, Isaac Pike, operated quar- 

 ries at Cummington about the year 1830. These quarries are not being 

 worked at present (1892), though in the ])ast they have sometimes produced 



