80 TRANSACTIONS OF THE [jAN. 13, 



shores than in the same latitude on the sea-coast. Lines drawn 

 through the points of equal terrace-altitude bore about N. 55° 

 E. This indicated that the terraces increased in lieight, not 

 directly from south to north, but in a direction normal to the 

 orographic axis to which the Cretaceous and Tertiary beds owe 

 their present attitude and elevation above tide-level. The terrace 

 heights were found to increase from about 25 feet in Cape May 

 County, at Beesley's Point, to about 80 feet on a line drawn 

 through Trenton and bearing N. 55° E. The slope thus indi- 

 cated is about one foot to the mile. 



Although this terrace-slope is greatest in a southeasterly 

 direction, there is necessarily a gentle slope toward the south of 

 a few inches to the mile. This was recognized by Prof. Geo. H. 

 Cook. 



The close parallelism of the strike of the Quaternary terrace 

 plane to that of the Cretaceous bed throws some light on the 

 orographic movements in this region during Mesozoic and 

 Cenozoic time. The strike of the Cretaceous Lower Marl bed, 

 as determined by Prof. Cook, N. 55° E., coincides very nearly 

 with the generalized strike of the Triassic strata at their south- 

 ern margin. The present attitude of the former is therefore 

 dependent upon orographic movements parallel to that which 

 primarily elevated the latter. One of these movements was pre- 

 Tertiary and caused the unconformity between the Upper Cre- 

 taceous and the Eocene ; another was the Quaternary differen- 

 tial elevation of the continental margin. 



The present attitude of the New Jersey Trias is evidently due 

 to an uplift along the gneissic axis which extends from West- 

 chester County, N. Y., through New Jersey to Trenton and 

 Philadelphia, and which will be referred to in the present paper 

 as the Trenton-Manhattan axis. At their eastern and south- 

 eastern margin the beds are parallel in strike to the gneissic rocks. 

 The dip of the former, except in the vicinity of the trap-sheets, 

 is uniformly toward the northwest or toward the pre-Cambrian 

 Highlands which border the Triassic basin in that direction. 

 The Triassic strata, where they adjoin these metamorphic rocks, 

 dip toward them. Their present attitude appears, therefore, to 

 be independent of any orographic movement along the axes of 

 the pre-Cambrian Highlands. There may have been differential 

 elevation throughout the whole of the Triassic area at the time 

 its beds were tilted, but, whatever theconditions, the uplift along 

 the Trenton-Manhattan axis was the greatest. 



The evidences of orographic movement along this axis have 

 long been known to the advocates of the Triassic arch theory. 

 These evidencesdo not require for their explanation, however, the 

 hypothesis that the Triassic beds were continuous in extent from 

 New Jersey into Connecticut. The first uplift along this line 



