182 ^ THE PlIEhfOMENA OF DRIFT, OR 



aqueous action. In some places the surface much resembles that 

 of the ocean in a storm ; that is, with troughs and prominences 

 jntermLxcd : but sometimes, as we look southeasterly, the surface 

 seems embossed more or less regularly, as in PL VIII, fig. 3, taken 

 a few hundred feet south of the summit, and embracing a space 

 of about five rods square. The same spot seen from another posi- 

 tion, exhibits more of troughs than the figure. Sometimes, as 

 neai* and a little east of the summit, we see on the southeasterly 

 side of the ledges, a space from which huge blocks, weighing 

 thousands of tons, have been removed by the agency that rounded 

 and furrowed the surface. Upon the whole, tliough the common 

 mai-ks of glacio-aqueous action are not strildng upon this moun- 

 tain, the embossed rocks are extremely so. 



After satisfying myself by repeated observations that the em- 

 bossed rocks could frequently be discovered where the strise had 

 been obliterated, it occurred to me that perhaps even the summit 

 of the White Mountains might retain the former appearance, 

 although I had reason to suppose the latter were not to be dis- 

 covered there. On those mountains, also, if any where in North 

 America, east of the Rocky Mountains, we might expect to find 

 traces of the existence and descent of glaciers in former times. 

 For excepting perhaps a peak in North Carolina, these mountains 

 are the highest land on the eastern side of our continent ; and 

 since they are composed of the oldest granite and mica slate, as 

 they were raised from the ocean they would form a centre, or 

 an axis of dispersion, from which glaciers would have carried 

 bowlders outw'ards, like the Alps in Switzerland, and the Gram- 

 pians, Ben Nevis, and the mountains of Cumberland and West- 

 moreland, in Great Britain. On the other hand, could evidence 

 be found on tlie summit of these mountains that glacio-aqueous 

 agency took a southeasterly course there, it would render it ex- 

 tremely probable that no such centres of dispersion exist in the 

 United States ; and that no true glaciers have descended from 

 our mountains. Stinuilated by such considerations, I determined 

 last summer (l^'4i) to visit the White Mountains. And allow 

 me here to say, that had no geological discoveries rewarded my 

 journey, I should have been amply compensated by the mag- 



