ABRADED AND PARTIALLY STRIATED TRIASSIC DIABASE BOSS IS SOLID PROOF THAT ABUNDANT EVIDENCE OF GLACIATION ON THE NEW JERSEY COASTAL PLAIN IS VALID

In N.J. beyond the Wisconsinan Terminal Moraine (WTM), there are Pleistocene surficial deposits which are mapped as older glacial drift in the western part of the state and as contemporaneous fluvial deposits in the eastern part. In 1891 Prof. Salisbury (glacial geologist from the Univ. of WI) was put in charge of the studies of these deposits by the NJGS.

Salisbury met with Chamberlin and Leverett in the western part of the state confirming the hypothesis of older (possibly two) ice invasions there. But for the SE part Salisbury in his first 1891 report stated “There is no evidence now in hand which indicates that ice ever invade southern NJ”. It was assumed that the older ice sheets terminated into the Raritan Bay and the Ocean. In the early years glacial features were described by his assistants. They suggested that glaciation be considered. Salisbury rejected the suggestion. He recognized many glacial features, yet insisted that “evidence is wanting” or that “there isn't sufficient proof” of glaciation beyond the WTM. The senior author's view would prevail! History repeating itself?

In his final 1916 report he concluded: The two Pre-Wisc. Coastal plain fms were deposited by large glacial outwash rivers, with ice rafting of boulders. The ancestral Hudson changed course from S to SW across the Raritan Valley and Bay, aggrading up (?) on to the coastal plain across the lowland down to Trenton on the Delaware R. and beyond (up to 200 ft. elevs.). The Raritan changed course from E to S, going up (?) the Millstone Valley, loaded with cobbles and 3 ft. boulders to Kingston, joining the Hudson.

What contained these river flows up to 200 ft. across dissected lowlands? The old reports are replete with a list of complex phenomena and questions that large rivers could not produce and explain; glaciation is the only complex, capable agent.

This year the writer discovered proof that Prof. Salisbury needed of glaciation beyond the WTM: an abraded and partially striated small Triassic diabase boss (not ice rafted) and other glacial features in the Rocky Hill area, 17 miles SW of the nearest WTM at Perth Amboy. This striated mass is the most positive proof (coupled with all the other abundant evidence) that the NJ coastal plain, was glaciated. Further, when this analysis is confirmed, in the field, there will be far reaching ramifications.