THE LONGMEADOW SANDSTONE. 365 



the first house south of Titans Pier, in South Hadley, and contains here 

 many curious inclusions of angular, flat pieces of a buff indurated clay, 

 which have been formed by the drying, cracking, and warping of a clay 

 bed exposed at low tide, and then the sweeping of the angular fragments 

 into their present position in the sand. It contains also scales of graphite 

 in considerable number, and this continues south to Holyoke in the sand- 

 stone and the tuff. The "fucoids" are especially abundant in Springfield. 



Forty rods north of the above quarry, at the west end of the sand- 

 stone bluff which overhangs the brook, and about 18 feet above the water 

 of the brook, which here runs on the Holyoke trap, there are many angular 

 fragments of limestone up to an inch in length. It is a coarse, crystalline 

 limestone, containing much tremolite, and more rarely plagioclase and 

 wernerite. 



This rock and the coarse scales of graphite came ];)robably from the 

 Archean area about the headwaters of the Westfield River, and after enter- 

 ing the basm were drifted northeast, Avith the prevailing current, to their 

 present situation, though there is a nearer and much more abundant 

 source for the graphite in the Brimfield schists to the east, and this schist 

 carries also thin beds of limestone with coccolite and garnet. 



FRAGMENTS OF WHITE TRAP WITHOUT AUGITE IN THE SANDSTONE ABOVE THE 



HOLYOKE SHEET. 



A tuffaceous agglomerate occurs in the second sandstone of the 

 Holyoke range, containing a colorless, wholly feldspathic trap. 



The great sheet of trap which forms Mount Holyoke flowed out 

 quietly and was immediately covered by fine calcareous mud in the cen- 

 tral parts and by coarser sands nearer the borders of the basin. I had sup- 

 posed that it remained covered during all the subsequent time of Triassic 

 deposition, and contributed nothing except by ferniginous solutions to 

 the sandstones that cover it. Recently my students in geology from the 

 senior class of 1896 at Amherst discovered an interesting dejiosit of tuff 

 between the Forest Park, or Little Mountain, plug and Mount Tom. It 

 lies in the bed of the brook which, flowing north between the main and 

 posterior sheets, crosses the railroad at the burnt mill north of Smiths 

 Ferry. The bed occm-s near the headwaters of the brook, below a bridge, 

 and is exposed for about 18 rods. It is a rather coarse, dark-greenish 



