Bulletin of the Museum of Comparative Zoology (Volume 49) (Paperback)

This historic book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1908. Not illustrated. Excerpt: ... removal by erosion, and perhaps also by displacement, of great masses of rock. The former idea may be called the narrow terrane view, the latter the broad terrane view. According to the narrow terrane view the Boston Basin and the Narragansett-Norfolk Basin may be considered as originally adjacent though separated areas of deposit or as separated members of one originally continuous basin. In either case, however, it is presumed that the combined area now occupied by the deposits of the several basins is approximately the same as that of the original deposit and that the latter was never very extensive. According to the broad terrane view the present deposits are downfolded or down-faulted remnants of a great mass of sediments which originally extended far beyond the present limits of the conglomerate areas but which have been removed by elevation above the plane of erosion or have been submerged beneath the sea. One of the strongest supporters of the narrow terrane view was Professor Crosby. In his Contributions to the geology of eastern Massachusetts he says (b, p. 181): "The Paleozoic rocks of eastern Massachusetts occur... .only in limited basins or depressions excavated in the ancient crystalline formations. Three of the basins have been recognized, and they are almost as well marked in the modern as in the ancient topography: for I hold the view that these basins probably existed as such before the deposition of the sediments which they contain." The results of later studies, showing the probable close relationship of the rocks in the three basins mentioned, have compelled a change of view so that the same author in a later paper speaks of the conglomerate as having been spread "far and wide over the entire region" (n, p. 464). Professor Shaler al...