682 B. K. EMERSON CIRQUES AND TERRACES OF MOUNT TOBY. 



Eight cirques have been cut deep into the heart of the mountain, so 

 that what remains is rather a set of steep-walled radiating ridges — a 

 skeleton of the former mass. 



It is tentatively assumed that these cirques are of glacial origin, be- 

 cause (1) they radiate in all directions from the center of the mountain, 

 and are so approximated as to leave apparently no place for the gathering 

 or outflow of running water by which they could have been carved; (2) 

 they have steep walls and a flat bottom, and head in a steep rounded wall 

 like the bergschrund of a glacier, and end in hanging valleys overlooking 

 the main basin of the Connecticut, and (3) in one case glacial scratches 

 remain in the side of a cirque running at right angles to the flow of the 

 main glacier, as described below. 



It is assumed also that they are of early glacial origin, because they 

 have no lateral or terminal moraines of local origin. Their bottoms are, 

 however, deeply covered by the general foreign till and their mouths are 

 sometimes clogged by the shore beds of the Connecticut Valley lake, 

 which followed the disappearance of the ice. They can not have been 

 produced by faulting, because the trap band crosses several of the more 

 important valleys continuously, and, as it has a very low dip to the east, 

 any faulting which could have caused these valleys would have made 

 great offsets in this trap sheet. Moreover, the heavy trap bed crosses the 

 bottom of several of the depressions and is planed down to the common 

 level, which is more indicative of ice than of water action. 



Starting at the southwest corner, there is an interesting double cirque 

 (a) (plate 30, figure 1) one-third of a mile wide, which appears to have 

 been occupied by a cascading glacier. 



The upper basin has a swampy bottom without inlets, and the steep 

 semicircular boundary wall can hardly have been worn by water. The 

 outflowing brook which jumps over the brink at the point indicated by 

 the cross in plate 30, figure 2, and into the deep lower cirque has not 

 worn back at all in the rock. 



Kext northwest there follows a very small corrie (h), with swampy 

 bottom and a fine hanging valley in the vertical wall (plate 31, figure 1). 



From a later examination it is believed that this small depression is an 

 early abandoned lobe of ''c," as shown in figure 1, plate 30. 



A wood road extends east into the mountain along the north side of 

 this corrie, and 88 rods up this road the pebbles of the conglomerate are 

 clearly polished and striated, the strias running south 15 to 20 west, and 

 18 rods farther on, where the road overhangs the brook, there are perfect 

 horizontal striae along the vertical wall, which there runs south 35 west. 

 These are directions following the axis of the valley at these points and 



