By Glenn L. Jepsen

Edited by GET NJ, COPYRIGHT 2003

Other questions were asked, some about the length of time since the bones had been part of a living animal and had been inside of hide and muscles, and other questions arose about the conditions in New Jersey when the creature had been a member of a herd of mastodons. Dr. Kemble Widmer, in order to help answer some of the questions about time and geology, has very kindly prepared the following report:

During the Pleistocene or Ice Age, parts of New Jersey were repeatedly covered by great continental glaciers. A terminal moraine (indicated on the map, page 10) through Metuchen, Summit, Dover, Hackettstown, and Belvidere marks the maximum advance of the late Pleistocene or Wisconsin glaciation. The retreat of the ice from this moraine was marked by readvances and further retreat before the final disappearance of the ice. The last of  the readvances, in middle Wisconsin times, sent a tongue of ice along the valleys of the Wallkill and Paulins Kill Rivers toward Belvidere. In the vi- cinity of Vernon this tongue of ice was bordered on the south and east by the Precambrian gneissic ridge of Wawayanda and Hamburg Mountains of the New Jersey Highlands (indicated on the map, page 15) and on the north and west by the Shawangunk conglomerate ridge of Kittatinny Mountain.

The position of the lateral or edge moraines south and east of Vernon suggest that for a long time ice occupied the valley but did not cover the mountain tops. Whenever the ice melted, the melt water would collect between the ice on the northwest and the gneissic ridges on the southeast and then drain off through the lowest open gap in the rock ram- part. One such gap, at an elevation of 1,240 feet, directly south of Vernon, was the site at which the mastodon was found, on top of a hard blue clay till and beneath about eight feet of peat, approximately at the watershed divide in the Vernon gap. An examination of topgraphic maps shows that this is the lowest outlet toward the south or southeast along about nine miles of mountain front between New Milford, New York and Vernon and Hamburg, New Jersey. Once the ice had melted back (north) or down (lower in elevation) far enough to uncover lower gaps east of Wawayanda Mountains, the outlet channel south of Vernon was abandoned.

The sequence of events between the abandonment of the outlet channel south of Vernon as an outlet for the ice margin lake bordering the middle Wisconsin ice tongue of the Wall- kill Valley and the death of the mastodon can only be inferred from several isolated bits of indirect evidence. A rather complete sampling of a section of peat, more than 15 feet thick, immediately west of the mastodon site was made by Dr. Sel- man A. Waksman, Chairman of the Department of Microbiology of Rutgers, and sent to the late John E. Potzger, Butler University, Indiana for a pollen count study. Unfortunately, however, Dr. Potzger could not determine from these samples the exact nature of the forest conditions at the time the mastodon died. He observed a large number of algal filaments and young prothalli of germinating fern spores in some of the peat, and pointed out that when fern spores germinate in water, they usually remain in the algal filament stage, and that this would suggest that the peat accumulaed not in a deep lake, but perhaps a wet depression rich in ferns.

In excavating for the mastodon, the personnel from the Bur- eau of Geology observed many short lengths of rotting `punky' wood, with pointed ends, and marks such as would be made by the chisel-teeth of beavers. As the excavation was drained by mud pumps, a small waterfall near the base of the peat, a few feet north of the site where the skeleton had been recovered, was caused by a large  number of these pieces of wood which were close together in the peat-probably the remains of a beaver dam.

Dr. Potzger's analysis of pollen in the peat samples at the 90-99 inch depth, approximately the level of the mastodon, indicates a forest cover of 36% White pine type, 26% Jack pine type, 20% Hemlock, 8% Oak, and 10% miscellaneous trees. There is no certainty, of course, that the mastodon died at this period of peat accumulation. It might have walked into the area at a somewhat later date, and its dying struggles or the weight of the bones after death may have caused the remains to sink into the older and deeper peat levels.

While the mastodon was being excavated, a sample of peat was taken from the horizon in which the bones had been found and this was submitted to the Lamont Geological Observatory of Columbia University for a radiocarbon age determination. Professor J. Laurence Kulp advised the Bureau of Geology that the peat sample No. L-231 is 10,890 years old, plus or minus 200 years, indicating that this peat 'was deposited at the very end of the Wisconsin rapid retreat.' Although the mastodon can be no older than this, it may be quite a bit younger, but it is felt that most of the peat in the area accumulated fairly rapidly during early post-glacial forest times before the area began to have the present topographic and climatic relations. The present forest cover consists predominantly of hardwoods, and although it is not well drained, it would not be considered a true bog, but rather a poorly drained forest area.

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