114 Kummel — Glaciation of Mountains in Pennsylvania. 



hardly be any doubt but that the whole knob was covered by 

 the ice. The amount of material left by it was, however, small. 



North of Dry Gap, as the col connecting the knob with the 

 plateau is called, the characteristic topography of the terminal 

 moraine is strongly developed. Fresh cuts along the recently 

 constructed line of the Wilkesbarre and Eastern railroad give 

 fine exposures of the glacial deposits. Since the data now at 

 hand prove that the ice covered the knob, the connection 

 between these two parts of the moraine is probably through 

 Dry Gap,* but the typical morainic topography is not developed 

 at that point. 



Sugar Loaf and Ararat, in the northwestern part of the State, 

 are 2475 and 2650 feet high,f respectively, and rise about 500 and 

 700 feet above the general level of the surrounding plateau. 

 Both are thickly covered with underbrush and timber, 

 and exposures are almost entirely wanting. On the north 

 face of Sugar Loaf, glacial material was found along an 

 old wood road, two thirds of the way up (as far as the road 

 extended). Above that height nothing definite could be made 

 out for lack of exposures. The surface, however, was not 

 radically unlike that of the lower part of the hill. The few 

 rock ledges which occur do not bear striae, nor have they roche 

 raoutonnee surfaces. However, ledges of sandstone so exposed 

 to the weather could hardly be expected long to retain glacial 

 markings. 



On Ararat the facts are much the same. From want of 

 opportunity for critical examination 1 was unable to prove that 

 the ice covered the highest points, nor was I able to satisfy 

 myself that it did not. 



Although in the present state of things, it is impossible to 

 obtain conclusive data, there are certain considerations which 

 indicate that the excepted view is probably not the correct 

 one. At the Delaware Water Gap, the ice filled the gorge and 

 overrode, with very little deflection, the crest of Kittatinny 

 mountain, which rises 1300 feet above the river and 600 to 

 700 feet above the general level of Kittatinny valley. If the 

 ice was of sufficient thickness to accomplish this at points less 

 than seven miles from its margin, it seems improbable that the 

 ice-sheet was not thick enough to override hills such as Ararat 

 and Sugar Loaf, which rise less than 700 feet above the sur- 

 rounding plateau, and which are seventy miles north of the 

 margin of the ice. There can be no doubt but that, were the 

 crests of these hills cleared and excavations made, traces of 

 glacial drift would be found here as at Focono Knob. 



Geological Survey of New Jersey, 

 Trenton, N. J. 



* This was suggested by Lewis in a supplementary note to his report (1. c, p. 

 271), although in the report he had mapped the moraine as extending around the 

 eastern end of the knob. 



f White, 1. c., p. 17. 



