near Mount Washington. 15 



and side walls. At first sight this block- strewn floor looked 

 promising. Bnt we soon found that farther down the valley, 

 in the half mile between Mossy Fall and its mouth, there is 

 nothing in the form of the floor that suggests morainic topog- 

 raphy. If this great cirque and trough had been filled by a 

 valley glacier in the closing stages of the glacial period, its 

 month should be encircled by a crescentic moraine, save where 

 Cold Brook might have excavated it. The fact is, there is no 

 such ridge of local debris. On the contrary, this lower floor 

 is occupied by a thick sheet of typical ground moraine which is 

 similar in composition to the till of the adjacent Randolph 

 Valley, and which blends with it. A count taken of the pebbles 

 in natural and artificial exposures of this till showed over 60^ 

 of material from outside the ravine, — much of itsnrely from the 

 northwest, and less than 40^ of the local mica schist. Striated, 

 subangular pebbles are plentiful. The large bowlders are nearly 

 all granites from the Orescent Range and Israel River Yalley, 

 a few miles northwest. Towards the side walls the ratio of 

 local to foreign debris naturally increases ; but over the greater 

 part of the valley floor the southeast movement of the till is 

 perfectly apparent. Forced by this evidence to admit that the 

 lower half mile of the trough of King Ravine had not been 

 occupied by a glacier since the disappearance of the ice sheet, 

 we sought consolation in the block deposit above Mossy Fall, 

 expecting to find there, at least, distinct records of a small, extinct 

 glacier. Several days spent in clambering up and down over 

 the blocks and in and out through the cavernous passages, and 

 in viewing the deposits of floor and sides from all angles, left 

 us very skeptical indeed as to the existence of even a short cirque 

 glacier here subsequent to the departure of the continental ice 

 sheet. That the huge mass of blocks came from the walls above 

 is clear enough ; but the fact that they seem to overlap the till 

 deposit of the lower floor at M'ossy Fall conveys the impression 

 that the block mass is a later deposit than the till, and perhaps 

 postglacial. On both sides of the ravine long talus cones or 

 "slides" appear, some fresh, some covered with good-sized trees. 

 They seem, however, to have little influence on the form of the 

 block floor. One line of exceptionally large blocks followed by 

 the "Subway trail" can be traced back to a prominent inclined 

 joint face on the head wall. This resembles some of the rock 

 falls described by Howe in the San Juan Mountains.* There 

 are deep furrows or linear depressions among the blocks, 

 especially near the foot of the side walls, yet the intervening 

 ridges lack continuity too much to be regarded as recessional 



*Ernest Howe : Landslides in the San Juan Mountains, Colorado, including 

 a consideration of their causes and their classification, U. S. Geol. Survey, 

 Prof. Paper No. 61, 1909. 



