FORMER GLACIATION OF NORTHEASTERN AMERICA. 383 



ward"* — to what point is not stated. The difficulties of the very general 

 non-coincidence of the striation with that which is demanded by this theory 

 are passed over by Professor Dana very lightly. The fact is, however, that 

 if we can place confidence in the work of the Canada Survey, and that of 

 Pi'ofessor Dawson, who has devoted much time to the study of the drift in 

 the St. Lawrence Vallej^, the direction of the strife and the character of the 

 surface geology in that region are decidedly opposed to the theory of a 

 continental ice sheet. The striation seems to be very generally limited to 

 the vicinity of the water-courses, and to be in a marked degree parallel 

 with them.t 



That some of the alleged facts by which the theory of a general ice sheet 

 extending over Northeastern America is supported are without foundation in 

 truth, may be unhesitatinglv alfirmed. Thus the constant]}^ repeated state- 

 ment that Mount Ktaadn in Maine has been covered with ice up to an 

 elevation of at least 4,385 feet above the sea is not in accordance with the 

 long-continued and careful observations of Professor Hamlin, who could find, 

 duriu"- three seasons of work on and about that mountain, no traces of 

 rounded and polished surfaces [roc/ics moutonnees) or of sti-iation upon it. 

 The occurrence of fossiliferous boulders, so often referred to as proof of the 

 presence of ice, cannot be accepted as such, in view of the fact that the 

 erosion of that region has been going on during indefinite geological ages, 

 so that the whole topographical aspect of the mountain and its vicinity 

 must have been very essentially changed from what it formerly was. That 

 Ktaadn should have been passed over or even surrounded by a sheet of ice, 

 variously estimated by the advocates of the theory of a continental glacier 

 at from two to twelve miles in thickness, and exhibit no other signs of such 

 an event than are offered by the occurrence of a few striated boulders of 

 foreign rock on its sides, seems to the writer incredible. $ 



* Manual of Geology, Third Edition, ISSO, p. 5S7. In the first edition of the same work (1S63) we find the 

 following : "The whole nortliern portion of the continent down to the soutliern linut of the drift was covered by 

 a vast and almost uninterrupted glacier." Motion was to the southward, because "to the north there was a uni- 

 versal barrier iu the ice and snow of the universal glacier. Motion would therefore have been mainly to the south- 

 ward, if it took place in any direction." 



+ The map given by Professor Dawson in his Notes on the Post-Pliocene Geology of Canada makes the south- 

 west direction of the striation altogether the predominating one on the north side of the St. Lawrence and the 

 Great Lakes, from Labrador to beyond Lake Superior. 



J See Bulletin of the Museum of Comparati%'e Zoology, VoL VII. pp. 214, 215. That the occurrence of .stri- 

 ated pebbles and boulders in the "slides" on Ktaadn is not by any means positive proof that a continental glacier 

 once passed over that mountain, is the decided opinion of the present writer ; but this subject will be alluded to 



