BETHLEHEM MORAINE 267 



ders] shows beyond a doubt that they came from the White Mountains 

 and not from the northern regions, since they overlie the typical drift 

 ■which they have only here and there removed or modified."* In one 

 instance, perhaps, Agassiz did consider the composition of erratics in 

 relation to that of the bedrock, for he says regarding certain "longitudinal 

 moraines" east of Mount Agassiz that they "are particularly interesting 

 as connecting the erratic boulders on the north side of the Franconia 

 Eange with that mountain mass, and showing that they are not northern 

 boulders transported southward, but boulders from a southern range 

 transported northward." 7 But nothing is said regarding the type of rock 

 concerned, and the context leaves one in doubt whether lithological re- 

 semblance was considered. Thus in undertaking to fit an alpine glacier 

 into a low undulating country along a path transverse to the slopes, in 

 its complete lack of evidence of grooving by the local movement, and in 

 its failure to furnish specific evidence of a northward dispersion of rock 

 debris from known sources, Agassiz's paper raises questions which could 

 only be answered by more critical field-work. 



Hitchcock's treatment of the problem places it more definitely . before 

 the reader, since it furnishes a larger number and variety of observations 

 and states more clearly the need for discriminating between the regional 

 glaciation and the local movement ; yet misgivings as to the conclusiveness 

 of the evidence are aroused by passages like those quoted in the following 

 sentences, with the addition of italics for the emphasis of significant 

 phrases : 



"He [Agassiz] found evidence of a movement opposite to that of the general 

 drift. Hence this must have been different from the common drift, and, taken 

 in connection with the other features described, it was found to have been 

 local, and existed in the decline of the ice period after the continental sheet 

 had mostly disappeared. The action was rarely sufficiently energetic to score 

 the ledges. Agassiz does not rely upon that class of evidence in maintaining 

 his position. The ice of this Franconia-Bethlehem movement has passed over 

 the ledges but has not smoothed or striated them. The boulders which went 

 southerly in obedience to the southeast movement were simply pushed back 

 towards their source ; and we find very few cases of their protrusion beyond 

 their starting point." s 



Turning to the White Cross Ravine ("the prominent valley back of 

 Eagle Cliff"), which was regarded by Agassiz as the source of that glacier, 

 Hitchcock devotes a page to a quotation from his father, Edward Hitch- 

 cock, who described moraine-like deposits made by new rock slides at the 



6 Op. cit., p. 164. The italics have been added. 



7 Loe. cit. 



8 Op. cit., p. 239. 



