1892.] NATURAL SCIENCES OF PHILADELPHIA. 481 



derived from the Medina group. Some of these occurred near the 

 Pattenburg cut, and at first deceived us. But subsequently we 

 found portions of this Triassic conglomerate in places in the cut, and 

 satisfied ourselves that there was nothing but local material there. 

 The gneissoid rocks have worked into the valley faster than the 

 Triassic, but at the same time the stream has cut down deeper on 

 the side occupied by the gneiss rock. There has been no inter- 

 mingling of material as there must have been had glacial ice covered 

 the whole area. Musconetcong Mountain was the limit of glacial 

 action east of the Delaware River and west of Bloomsburg. 



These inferences are confirmed by the absence of evidences of the 

 action of land ice in the country on both sides of the river south of 

 this point. From Riegelsville, near the mouth of the Musconet- 

 cong River, we drove to Bursonville, several miles out over the 

 Triassic plateau which there extends beyond the Archjean outcrop, 

 which rises several hundred feet on the south of the Lehigh, and 

 where, if there had been any southern transportation by land 

 ice, the remains would be most likely to be seen. But there was 

 not the least sign of foreign material to be found. We drove out on 

 both sides of the river at Lambertville, some distance down toward 

 Trenton, with the same result. Professor A. A. Wright drove 

 from Flemington across Sourland Mountain with the same result. 



Along the Delaware we found distinct terraces both of Trenton 

 and Columbia gravels. At Riegelsville the Columbia was well 

 developed in an extensive terrace, preserved in an ox bow of the 

 valley at a height of 175 feet. It had all the characteristics of the 

 Brick Clays and Red Gravel at Philadelphia and other places 

 below. 



In addition to these detours we took the ride along the North 

 Pennsylvania Railroad, from Bethlehem to Philadelphia, which 

 passes over Mesozoic deposits for a distance of 25 or 30 miles, and 

 shows almost a continuous section of the surface soil. There is no 

 foreign material in it or on it. The same is true in New Jersey in 

 the sections shown on the railroad from South Plainfield to Flem- 

 ington, and from Bound Brook to Trenton. 



The deposits at Fallsington belong to the Columbia. They are 

 related to the river level, and are not higher than those at Philadel- 

 phia. The occurrence of scratched stones in them simply teaches 

 thatfloatingicecan transport material without effacing all scratches. 

 At Bridgeport, opposite Norristown, on the Schuylkill River, there 



32 



