Abstract

Five tills and intertill beds are described: an upper till with two components—sandy till (till 1) and clay till with almost identical rock (till la)—and three older clay tills (tills 2, 3, and 4) with glaciated pebbles of different kind of rocks from those in tills 1 and la. Intertill beds were found between all these. The tills seem to have a wide distribution on eastern Cape Cod, and preliminary work indicates that they may extend to western Cape Cod and the mainland. The clay tills contain marine sponge spicules, several species of marine diatoms, a few Radiolaria, and abundant pollen grains and spores of many species of plants. Tills 2, 3, and 4 are much alike both in pebble content and the contained microfossils. At Nobscusset Beach fragments of wood and a pollen flora collected from sands between tills 2 and 3, and between 3 and 4 suggest a climate as warm or warmer than the present. At Highland Light in a sand under a gravel, which in turn underlies clay (Gardiners ?), is a cool climatic flora. Glaciated pebbles and boulders, frigites, the lack of stratification, together with the fossil content suggest that the boulder-bearing clays on Cape Cod are actually tills. It is judged by the authors that tills 1 and la originated from a different ice sheet from the one which deposited tills 2, 3, and 4. The fossils in the tills and intertill beds, it is believed, have been derived largely from an older interglacial marine deposit. There is evidence from the study of peat deposits and associated beds in the area for the late Wisconsin age of till 1 and la. Nothing indicates an age older than Wisconsin for tills 2, 3, and 4 and therefore the whole series is believed to be of this age.

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