GLACIAL DRIFT. 207 
blocks is quite extensive and comparatively level, it is fair to conclude that the trans- 
portation has been affected by the glacier and not by frost. The latter agency, how- 
ever, has very industriously operated upon both ledges and boulders in post-glacial 
times, so that the shattered ledges, their fragments, and the fractured boulders form a 
continuous field of angular débris over the whole upper cone of the mountain. 
From these facts, the following conclusions seem legitimate: 
1. The glacial ice completely covered and passed over the summit of Mt. Washing- 
ton in a south-easterly direction. 
2. It brought along a large amount of moraine rubbish and glaciated stones, which 
were disposed in various hollows and convenient locations about the mountain, in the 
same way that the ground moraine is distributed in the lowlands. 
3. Subsequently an immense number of large blocks of stone, taken from the north- 
ern slope of the mountains, were transported to the summit (as well as beyond), and 
left overlying the finer earth débris of a previous transport. 
4. Frost and gravity have been acting upon the boulders thus transported and the 
ledges, so that every large block has been split up into smaller ones; and this angular 
débris entirely conceals from view the previously formed moraine, and the summit is 
apparently destitute of soil. 
After the announcement of this discovery, it was objected by some 
that these transported foreign stones might have been brought by team- 
sters or by the railroad. It was said to be a common custom for the 
men to place canvas over articles in their vehicles for protection, and to 
fasten down the cloth by stones. On reaching the summit, the stones 
would be thrown away, and perhaps the glaciated bits might be some of 
the fragments thus transported. The boulders I found were not over 
two pounds in weight. These would hardly be sufficient to hold canvas 
down in a wagon in the teeth of the formidable winds often blowing at 
the summit. Still, I thought it best to search further in localities not 
reached by débris. About fifty feet below the summit, midway between 
the railway and carriage-road, I soon found a rounded block of light gray 
Bethlehem gneiss weighing ninety-one pounds, evidently the rock that is 
common about Jefferson, but very different from the material composing 
the mountain. It lay beneath other fragments of stone, partly embedded 
in earth, and showed patches of the common yellow lichen of the summit 
growing upon it, older than the date of the building of either road. TI 
therefore concluded that no human agency ever brought this heavy stone 
and planted lichens upon it; nor is it probable the ones first discovered 
reached the summit except as borne by ice. Hence the proof of the 
