of
the Channels Surrounding Manhattan Island, N. Y."( Bulletin Geological
Society of America, Vol. xvi, pp. 151-182) ; contains useful line
sketches of sections.
In
1905, Dr. J. W. Spencer published his " Submarine Canon of the Hudson "
in the American Journal of Sciences (4th Series, Vol. xix, p. 1),
amending Lindenkohl's survey.
In
1905, Professor Lewis M. Haupt, " New York Harbor and its Improvement,"
American Association of Advanced Science. Title only found in published
volume of the Association.
In
1905, W. T. Schaller, in " Contributions to Mineralogy" (Bulletin
United States Geological Survey, No. 262, p. 94), describes Dumortierite from Manhattan Island.
In
1906, Dr. A. A. Julien published his " The Occlusion of Igneous Rock
Within Metamorphic Schists as Illustrated On and Near Manhattan Island,
New York," in which he describes the belt of hornblende gneiss at
Spuyten Duyvil.
In 1907, " Physiography of the Lower Hudson Valley," Professor J. F. Kemp (Bulletin Geological Society of America, May, 1907).
In
1907, " Limestones of Westchester and Putnam Counties, New York,"
Professor Charles P. Berkey; a study of the variations and comparisons
of the relationships of the formations characteristic of the Highlands
region of New York.
In
1907, " Structural and Stratigraphic Features of the Basal Gneisses of
the Highlands," Professor Charles P. Berkey. An epitomized statement of
very considerably extended and detailed field-work. The author defines
a basal central massif of variously composed gneisses much
dissected by faults and injected with granites, diorites, and gabbros,
and this pre-eminently concentrated in the Highlands. Over the basal
gneiss he formu^ lates two groups of formations—a northern—phyllite or
slate ("Hudson River"), fine-grained blue and white banded limestone (" Wappmger"), a fine-grained quartzite (Poughquag, not Lowerre)—and a southern—coarsely crystalline mica schist, pegmatitic (Manhattan), crystalline limestone (Inwood), a quartzite (Lowerre)—These two groups are nowhere in contact with each other. The southern (forming New York Island, etc.) conforms well with the basal gneiss, and is pre-Cambrian. The Lowerre quartzite is a phase of the Fordham gneiss simply.
