50 H. B. KUMMEL 



steep the accumulation of these residuary materials in a thick 

 mantle would seem to have been improbable. But the size of the 

 materials handled by the streams during the Newark time indi- 

 cates a velocity inconsistent with streams on a peneplain. It 

 would seem, therefore, that with the beginning of the Newark 

 deposition the land regained something of its former eleva- 

 tion. The rivers were able to carry from the crystalline areas 

 pebbles of quartz or feldspar several inches in diameter and to 

 handle quartzite cobbles ranging up to a foot in size. 



The massive border conglomerates are probably not com- 

 posed entirely of stream-transported material. Limestone bowl- 

 ders poorly rounded and measuring four feet in diameter have 

 been seen, and some twelve feet in diameter are reported to occur 

 in the calcareous conglomerates. All the coarser border con- 

 glomerates were probably accumulated by the waves which beat 

 against limestone and quartzite ledges. The scarcity of gneissic 

 conglomerates indicates that the shores were not chiefly gneissic, 

 as would be the case today were the Newark area to be sub- 

 merged, but of limestone and quartzite. The faults along the 

 northwest border have, for the most part, cut out these rocks, 

 and brought the Newark beds against the crystallines. 



That the sandstones and shales were accumulated in shallow 

 water, is shown by the ripple marks, mud cracks, raindrop 

 imprints, and footprints of reptiles and other vertebrates, which 

 occur at all horizons. At no time apparently was the water of 

 the estuary so deep that the outgoing tide did not expose broad 

 areas of sand or mud. It follows from this that there must have 

 been a progressive subsidence of the estuary during the deposi- 

 tion of these beds, since their thickness is to be measured by 

 thousands of feet. The subsidence went on pari passu with the 

 deposition of the sediments, since the shallow-water conditions 

 prevailed continually. The progressive elevation of the adjoin- 

 ing land areas, shown by the material carried by the rivers, was 



to the surface on which the Newark beds in Connecticut were deposited. His argu- 

 ment, however, was along an entirely different line of reasoning, being based upon 

 the present topography. 



