Bridgeton Formation — Summary. 21 



If the above view concerning the origin of the Bridgeton is 

 correct, corroborative evidence might be expected on the Penn- 

 sylvania side of the Delaware, and along the northwest side of 

 the Amboy-Bordentown lowland. The evidence afforded by 

 these regions is meager, though consistent with the view stated 

 above, so far as known. Gravel and sand which may be inter- 

 preted as remnants of the Bridgeton formation are found on the 

 west side of the Delaware at various points between Trenton 

 and Chester ; but they are so meager as to leave any conclusion 

 drawn from them open to question. If they are remnants of 

 the Bridgeton formation, their meagerness may find a sufficient 

 explanation in the fact that the Delaware flows near the western 

 edge of the supposed pre-Bridgeton valley, and that the Bridge- 

 ton formation has therefore been more completely removed from 

 this side of the valley. When the narrowness of the tract on 

 the west side of the stream low enough to have received Bridge- 

 ton deposits is considered, it is unlikely that considerable rem- 

 nants of the formation would have escaped erosion. The case 

 is much the same northwest of the Bordentown-Amboy valley 

 in New Jersey; but evidence that the Bridgeton or some forma- 

 tion similar to it once covered this region, is conclusive. 



Northeast of Berlin, Bridgeton remnants in the old Amboy- 

 Bordentown valley are absent, or, if present, have not been 

 identified. It is probable that no deposits of this time, made 

 by drainage through the main valley, persist. 



This conception of the origin of the Bridgeton formation is 

 not without difficulties. It is not clear, for example, how streams, 

 even with the help of floating ice, could have carried bowlders 

 and large slabs of weak rock from the Newark series, to Ham- 

 monton, New Germany (Folsom), and Buck Hill. If streams 

 were the agents of transportation, the course of drainage must 

 have been very different from that of the present time, and there 

 is some evidence that it was not. If, on the other hand, the 

 bowlders and slabs of weak material were floated to their desti- 

 nation in sea water, a submergence of more than 100 feet would 

 be called for, and of this there is no cldar evidence. If the master 

 stream of southern New Jersey flowed further east than the 



