480 PROCEEDINGS OF THE ACADEMY OF [1892- 



Scott's Mountain, (400 feet above the river Pohatcong. and 

 600 above the Delaware), and continues to Brass Castle, on 

 the Pohatcong. On going still fiirther west, we found the 

 same continuity of foreign boulders extending through Har- 

 mony over Marble Mountain, a projection of Scott's Moun- 

 tain, while the plain bordering the Pohatcong Creek was 

 deeply covered with Medina and Oneida boulders down to the 

 vicinity of Phillipsburg. These must have been derived from the 

 deposits which had been brought over from Scott's and Marble 

 Mountains by glacier ice. Going still farther south on this line 

 within five miles of the Delaware, we found Medina and Oneida 

 boulders all along to the summit of a col on Musconetcong 

 Mountain, two or three miles west of Bloorasbury, and at a height 

 of something over 500 feet above the river. Here a boulder of 

 Medina was found measuring 3x25x1 feet. Another still retained a 

 A'^ery perfectly scratched surface. 



The other portions of the mountain here rose about 200 feet 

 higher than this col, and upon them we failed to find foreign boul- 

 ders. But on following down a small stream leading south to 

 another Little York on Hikihokake Creek, bordering the Triassic 

 shales, which here begin, we found many pebbles of M edina sandstone 

 distributed about its ancient delta. But they did not extend far out 

 on the Triassic deposits. A long detour upon these showed that they 

 were perfectly free from foreign material. Though flanking the 

 gneissoid rocks of Musconetcong Mountain, which rises several 

 hundred feet above them, there has been no southern transportation 

 of material over that area since the original deposition of the 

 Triassic period. This seems to prove conclusively that glacial ice 

 once extended within five miles of the Delaware River, as far south 

 as the summit of Musconetcong Mountain and no farther. 



Some facts in confirmation of this inference occur at Pattenburg, 

 which is just over the watershed to the east, leading into the Raritan 

 River, and not more than seven miles distant. The supposed glacial 

 deposit there lies near the headwaters of Mulhockaway Creek, which 

 in the upper part separates the gneissoid rocks of Musconetcong 

 Mountain from the Triassic rocks to the south. The Triassic rocks 

 rise upward of 400 feet above the stream on the south, while the 

 gneissoid rocks rise about the same height on the north. The 

 Triassic deposits are here of a conglomerate character, often con- 

 taining pebbles a foot in diameter, some of which seem to have been 



