Wilson — Glaciation of Orford and Sutton Mts., Quebec. 201 



locality where the striations were noted, is a furrow about 

 three feet in depth and of slightly greater breadth, partly filled 

 with loose debris at its southeast end. The form and shape 

 of the hollow suggest that a joint block was removed by the 

 ice and that the cavity was afterwards somewhat rounded out 

 by the corrasive action of the ice sheet. 



The soil at the summit consists in part of a sandy material 

 containing many small chips and fragments of loose rock. 

 The writer made a collection of rounded, subangular, and 

 angular fragments derived from 12 different kinds of rock, 

 all of which were foreign to the summit of the mountain. 

 Among the fragments are pieces of schist from near the base, 

 and a number of small pieces of pink granite, gneisses of sev- 

 eral types, and vein quartz. Hitchcock also has recorded the 

 finding of a fifteen-pound bowlder of gneiss in the same local- 

 ity. The latter fragments are all unquestionably derived from 

 the rocks to the north of the St. Lawrence river. The greater 

 portion of the soil at the summit consists of a slightly arenace- 

 ous fine-textured grey clay which assumes a greyish-white 

 color on drying. A qualitative chemical and a microscopic 

 examination showed the presence of very small amounts of 

 iron salts and of carbonates. Quartz sand is present in con- 

 siderable amount, approximately 8 per cent, and the balance 

 consists chiefly of kaolin, with a small percentage of mica, 

 probably sericite. 



A soil derived from the disintegration of the diabase of 

 which the summit of the mountain is composed would be 

 expected to contain much larger amounts of carbonates, would 

 show a very much larger percentage of iron salts, and would 

 normally be free from quartz. It is recognized that by the 

 process of leaching the excess of the carbonates and of the iron 

 salts might be removed in some cases, and that the quartz 

 might be formed by the decomposition of the silicates. In 

 this locality the soil is fine-textured close to the bed rock and 

 it is not found to gradually grade downward into the underly- 

 ing unclecayed rock. It is also to be noted that this soil occurs 

 less than three feet vertically below and horizontally, within a 

 very few feet of the highest point of the mountain, and there- 

 fore it is not in a position favorable for the leaching action of 

 soil waters. On the other hand, not only is the soil similar to 

 that which is normally produced by the disintegration of the 

 Archean rocks to the north, but also when its character is con- 

 sidered in conjunction with the other features already de- 

 scribed, the cumulative evidence is such as to lead one to the 

 conclusion that this soil also is of exotic origin. Since it is 

 found to contain only a very small percentage of carbonates, 

 one would infer that the limestones in the plain to the north 



