BETHLEHEM MORAINE 277 



too feeble and short lived to make a true cirque out of it. Along the 

 sides of the brook, from the base of the ravine head for about a mile 

 down valley, blocks and smaller fragments of rock are massed in curious 

 linear ridges or mounds, which run longitudinally — never transversely — 

 to the ravine. Doubtless they are landslide deposits like the one which 

 Edward Hitchcock observed and described in 1850, the year after it fell. 1 " 

 The steep sides of the ravine within a mile of its head are covered with 

 loosely packed blocks, which, half buried in moss and clothed with a 

 struggling spruce and hardwood forest, offer footing which is precarious, 

 even dangerous, to pass over. With the possible exception of a slight 

 sapping and steepening where the valley heads against the peaks of 

 Lafayette — work which might be accomplished by nivation — I can not 

 see that local glaciation has been recorded here. The oversteepened con- 

 dition of slopes which gave rise to the landslides is adequately accounted 

 for by regional glaciation. It is a condition not confined to the valleys, 

 but met with also on mountain flanks which overlook broad lowland 

 districts. 



CONCLUSIONS FROM EVIDENCE IN THE BETHLEHEM DISTRICT 



Agassiz's view that the Bethlehem moraine was deposited by a local 

 glacier, descending northward from the Franconia Mountains, is rejected 

 for the following reasons : 



1. The topography between Mount Lafayette and the Bethlehem 

 moraine is inhospitable for a glacier of the alpine type, offering no con- 

 tinuous downhill path, but requiring an open, cross-country course of 

 considerable relief. 



2. At the alleged source of the glacier — the White Cross Bavine — as 

 well as in the neighboring ravines, no cirque cutting or trough cutting 

 is evident. 



3. The moraines compose a wide belt which trends northeast-southwest 

 for several miles, at least, without relation to the narrow course which 

 Agassiz assigned to the local glacier, and without the northward con- 

 vexity which his theory would require. 



4. There is no trustworthy evidence that drift material has traveled 

 northward to the moraine. 



5. All observed stria? and grooves can be referred to the southward 

 movement of the continental ice-sheet, as Agassiz and Hitchcock did 

 refer them. 



18 E. Hitchcock : Description of a slide on Mount Lafayette, at Franconia, New Hamp- 

 shire. Amer. Journ. Science, 2d series, vol. 14, 1852, pp. 73-76, 



