162 KUMMEL AND WELLER — LIMESTONES OP KITTATINNY VALLEY 



The greater thickness of the tbrmatioii at its southeastward exposures, 

 as compared with the westward outcrops, points to the existence of land 

 to the southeast of the present highlands, conclusions which are in 

 accord with those of workers in Pennsylvania and farther south. 



Durhig the formation of the Kittatinn}'- limestones the waters were not 

 deep, as wave marks occur at various horizons. The thin partings of 

 shale or of sandstone in the limestone show that at intervals land de- 

 rived mechanical sediments were present in sufficient amount to inter- 

 rupt the formation of the dolomite; but in general the sea was remark- 

 ably free from sediment. The limestone exposed within the highlands 

 or along their southeastern flank do not in themselves show a greater 

 proximity to a shore than do those of Kittatinny valley, 20 miles or more 

 to the northwest, and therefore that distance farther from the shoreline 

 of that period: During this time the shore must have lain far east of its 

 position during the formation of the Hardiston quartzite and a consider- 

 able distance east of the borders of New Jerse3\ In this, also, our studies 

 are in accord with tlie conclusions of those who have studied these lime- 

 stones farther south. * 



During the later stages of this period changes in the sea began, in 

 consequence of which non-magnesian limestones alternated in deposi- 

 tion with the dolomites. Leslie^ has shown that in southeastern Penn- 

 sylvania dolomitic and non-dolomitic beds alternate in shar])ly differ- 

 entiated layers in the lower middle of the formation, due, he thinks, to 

 alternating conditions of deposition ; but there is nothing in the analyses 

 of the New Jersey limestones to indicate that the changes began as early 

 as in Pennsylvania. 



The Trenton conglomerate and the slight unconformity betwe6n it 

 and the Kittatinny limestone indicate an u})lift of the sea bottom, 

 erosion, and the prevalence of shore conditions in northern New Jersey 

 and the neighboring region to the north. Our own studies have not 

 extended north of New Jersey, but the occurrence of the Trenton con- 

 glomerate in southeastern New York is clear from the studies of others. 



An exposure of it two and a half miles north of Newburg, New York, 

 is pictured by Ries,t although he does not mention it in his text. Con- 

 cerning this outcrop Mr Gilbert Van Ingen, who took the photograph, 

 writes : X 



" The rock shown in tlie picture is a dark, impure limestone with many pebbles 

 of the dolomitic lower Ordovician limestone. . . . The pebbles in the lime- 

 stone are sometimes three inches in diameter." 



♦ Second Pennsylvania Survey, M. M., pp. 360, 36L 



t Report of the State Geologist of New York, 1895, report on Orange county, pi. xxxi. 



J Personal letters to the authors. 



