SILURIAN SCHISTS ON EAST SIDE OF VALLEY. 243 



THE zo5^:e of contact around the belchertowx toxalite. 



THE PYROXENIC AMPHIBOLITES. 



An iuspectioii of the map will show that the crystalline rocks are 

 thrown off on all sides from the flanks of the great Belchertown "batholite," 

 and that great sheets of the same rest on the tonalite far out in the center of 

 the mass. These are of the varieties most characteristic of intense contact 

 metamorphism — coarse fibrolite- and pyroxene-schists, epidosites, and highly 

 silicified gneisses and quartzites. 



The zone of crushing following the foothills through Leverett, Pelliam, 

 and Belchertown passes directly through this contact border and materially 

 increases the difficulty of identification and correlation of the beds with 

 their equivalents elsewhere. 



It is not possible to distinguish between the beds below and those 

 above the amphibolite, since the quartzite becomes heavily loaded with 

 biotite, fonning a fissile gneiss, which I have found all around the mass and 

 have in my notes called the Baggs Hill gneiss, from its abundant develop- 

 ment in this hill in Granby near the Belchertown line. As soon as it 

 approaches the granite mass the amphibolite becomes pyroxenic, as at Kel- 

 leys Crossing and on south down the west side of the mass, while the Con- 

 way schists become coarse fibrolite-gneiss and epidosite. 



The baud of amphibolite which was traced through Leverett to Adams's 

 mills reappears between the two Belchertown ponds and wraps around the 

 south end of the Pelham gneiss, uniting the Leverett-Amherst area and 

 the Pelham-Shutesbury syncline, and extending across Belchertown Center 

 with great width because of the disturbing influence of the tonalite. It is 

 much shattered, and swarms with small aplitic dikes from the tonalite.- 



A sahlite-amphibolite appears at the point where the road from Amherst 

 to Belchertown crosses the railroad — in the new cutting of the Massachu- 

 setts Central Railroad — and a short distance farther south in the cutting of 

 the New London and Northern Railroad at the next crossing (Kelleys 

 Crossing). 



Here the rock is a coarse amphibolite of dark-green color, made up 

 almost wholly of broad, interlacing plates of hornl)lende. It is much cut 

 by dikes of a flesh-colored granite (aplite) containing little mica, which send 

 small veins through it in all directions, recementing the brecciated mass. 



