CORRUGATION AND CRUSHING BY ICE. 179 



Nor arc the phenomena above referred to restricted to the New Jersey 

 side of the Delaware. South of South Bethlehem, in Pennsylvania, the 

 same materials occur several hundred feet above the Lehigh valley. 

 Finely glaciated bowlders imbedded in clay have been seen at more than 

 one point south of the Lehigh at distances from the moraine comparable 

 to those at which occur the Pattenburg and High Bridge deposits al- 

 ready referred to. In Pennsylvania, as in New Jersey, the material has 

 a vertical range of several hundred feet. 



Direct Evidence of Ice Work. — In the eastern part of New Jersey, near 

 New Brunswick, some six miles from the moraine in direct line and at 

 an elevation of 100 feet, there are some recently exposed sections which 

 show a bowlder-bearing clay with rarely a glaciated bowlder resting on 

 an irregular surface of Triassie shale. The irregularity is not of such a 

 character as would be produced by erosion. It bears evidence rather of 

 mechanical disturbance. In many places the stratification planes of the 

 shale have been obscured by the crushing of the shale, but in other places, 

 where the crushing effect has been less, the shale appears to have been 

 pushed up into folds two to four feet high and with a width about equal 

 to their height. In some cases these folds have been pushed over to one 

 side, the bowlder clay wrapping around the inclined folds, lying beneath 

 as well as above them. In other cases where stratification planes have 

 been obliterated, or so nearly obliterated as to make their position indis- 

 tinct, there are other phenomena exhibited scarcely less significant than 

 those mentioned in determining the origin of the bowlder clay. There 

 are places for considerable stretches where the material overlying the 

 shale is essentially composed of red shale crushed to small fragments, or 

 reduced to clay. This takes the place of the transported material which 

 overlies the shale elsewhere. In the midst of such masses of broken 

 shale, strictly local in origin, occasional bowlders of transported material 

 occur, even down to the surface of the bedded shale. Exactly correspond- 

 ing phenomena may be observed in many glaciated regions where the 

 underlying rock is soft, or where a great amount of residuary material 

 was accumulated on the surface prior to glaciation. It is quite compre- 

 hensible thai such relations could be brought about by glacial action, but 

 it is difficult to conceive how such results can be achieved by any other 

 agency. At one other locality, fifteen miles southwest of New Bruns- 

 wick, similar phenomena may be seen, though less strikingly developed. 



Distribution of the Phenomena. — No determinations have yet been made 

 as to the southern limit of this bowlder-bearing day. The points in 

 New Jersey and Pennsylvania mentioned above, however, are not the 

 southernmost Localities where glaciated material is known to occur. 

 Striated bowlders have been found hoth hv Mr. Charles E. Peel and the 



