Davis.] 118 [November ] } 



eral statement may therefore be made that in either region, the 

 dip of the strata, the back of the trap-ridges and their concave 

 sides are all turned one way ; eastward in the Connecticut Val- 

 ley : westward (or west-north-west) in New Jersey. 



The uniform dip or monoclinal arrangement of the sandstone 

 in either strip is very peculiar ; and it has seemed so difficult to 

 account for it by any supposition of disturbance in originally 

 horizontal sandstone patches of about the present area, that two 

 explanations have been suggested to avoid this difficulty. 



In 1839, H. D. Rogers, then State Geologist of Pennsylvania, 

 proposed that the monoclinal dip should not be considered the 

 effect of disturbance after deposition, but should be looked on as 

 the result of original oblique deposition — as cross-bedding on a 

 great scale. He thought that the long Virginia, New Jersey strip 

 was a deposit in a noble river that rose in the mountains of North 

 Carolina and flowed north-easterly to the Atlantic about at New 

 York Bay ; and as all these sediments have a north-westerly dip, 

 they must have been washed into the river from its south-eastern 

 banks ; the departures from the general dip were considered the 

 effects of eddies in the mighty river. A similar explanation was 

 applied to the Connecticut area. Now apart from the inherent 

 improbability of cross-bedding on this vast scale, a very serious 

 objection to the theory is found in the coarse conglomerate de- 

 posits very commonly found on the dip-side of each estuary ; on 

 the north-west in New Jersey, on the east in the Connecticut 

 Valley. These cobble-stones and pebbles have in many places been 

 traced to their sources in the neighboring hills or banks of the 

 old estuaries ; when they were washed into the water, there must 

 have been also a large quantity of fine detrital material carried 

 along with them, and deposited as a rule farther from shore. But 

 how could all this sediment be deposited dipping toward its 

 source as it is now found ? This is a mechanical impossibility, 

 and is alone sufficient to negative the theory of cross-bedding. 

 The detritus washed into the Connecticut estuary from its east- 

 ern side must have originally lain in horizontal strata or dijjped 

 gently to the west ; and the fact that these strata now dip 

 distinctly to the east is ample proof that they have been dis- 

 turbed since their deposition. 



