MUSEUM OF COMPAEATIVE ZOOLOGY. 217 



making the elevation of the head above the foot about 1,200 feet. It 

 had its origin in an avalanche which is said to have descended between 

 1820 and 1830. The two slides will in time disappear, as others before 

 them doubtless have, by the slow encroachment of shrubby growth from 

 the bottom and sides, now seen to be in progress. On the East Slide 

 much less drift is found than on the other. Outside of the slides, I 

 have never found drift upon the flanks of the mountain ; but it re- 

 appears higher up, in very small amount on the Table Laud, but princi- 

 pally iipon the northern summits, sparsely strewn among the broken 

 granite that covers them. Neither on slides nor summits is the drift 

 ever found in large bowlders, but always as fragments of moderate size. 

 On the Southwest Slide a fexo masses were seen as heavy as a hundred 

 pounds each, but in general — always upon the East Slide — the pieces 

 ran from a few ounces up to twenty pounds in weight. They were 

 chiefly fragments of slates and sandstones, identical with the strata of 

 the country north and west, mingled with pieces of metamorphic and 

 trappean rocks, such as occur in place for a few miles beyond the Ripo- 

 genus Carry. 



The fragments of stratified rocks on the Southwest Slide very gener- 

 ally include fossil shells, mainly Brachiopods, and always impressions or 

 interior casts. Owing to the small size of the enclosing masses, — due 

 to the fissile structure of the rocks, — the fossils ordinarily are much 

 decayed, but occasional specimens are obtained in fine condition. Among 

 the scanty drift upon the upper third of the Southwest Slide, I have 

 never seen a fossil-bearing stone. And upon those parts of the summits 

 where drift was found, only once was a fossil met with, — a solitary 

 Brachiopod impression on a ten-pound piece of sandstone, picked up on 

 the slope northward from West Peak to the Saddle, about 600 feet be- 

 low the top of the peak, or at an elevation of about 4,615 feet above the 

 sea. This is by far the highest point at which fossiliferous rocks have 

 yet been found upon Ktaadn.* 



* Dr. De Laski's statement of the height (4,385 feet) at which he found fossils, 

 "well up toward the 'Horseback' ridge" (Am. Jour. Sci., [3.] III. p. 27), and 

 which is quoted by Prof. Dana in his Manual of Geology (editions 2d and 3d), 

 is founded upon a wrong estimate of the altitude of the mountain. He adopted 

 the one current for some years before Prof. Fernald's remeasurement of the eleva- 

 tion, which he made to be 5,215 feet. Xow the elevation of the "Horseback" 

 ridge, at a point directly up from the head of the East Slide, — Dr. De Laski's 

 route, — we make 1,181 feet above Basin Pond, while that of the summit of Ktaadn 

 is 2,287 feet above the same level. The difference 2,287 — 1,181 =1,106 feet, the 

 difference of elevation between the "Horseback" ridge, at the point named, and 



