Boston Meeting of the Geological Society. 143 
sometimes plainly connected with the crumpling of the gneisses, but in 
the massive varieties this is not evident ; in all cases it is inherent in 
the form of the minerals themselves, which have a more or less marked 
longer axis in the direction of the "pitch"' and show no sign of mechani- 
cal strain, so that they must have crystallized under conditions com- 
pelling them to take this form. The problems connected with the areal 
geology of the region are as to the origin of the rocks. 
The Hibernia region specially described contains one of the largest 
ore deposits of the State, which is in bed form, having a mile of outcrop 
and having been worked in the dip 600-700 feet down. This strikes IN. 
E., with a moderately steep dip S. E. The gneisses on the foot-wall side 
of the ore bed show generally imperfect foliation, but very distinct pitch, 
which can be followed several miles S. W. from the ore-bed ; just oppo- 
site the north end of the ore outcrop the pitch is replaced by a N. W. 
strike of the gneisses and a N. E. dip in the direction and with about 
the angle of the former pitch. In this way individual beds of gneiss 
can be traced from both the foot and hangiDg wall sides of the ore into 
this northeastwardly dipping series, which gives us a true stratigraphic 
section of several thousand feet in thickness measured on the axis of 
the dome. This series to the west loses its banded character and turns 
into northeastwardly striking and pitching gneisses. As further proof 
of the stratigraphic order of this series, a band of distinctive rock con- 
taining garnets, biotite, and graphite, lying many hundred feet above 
the ore, was traced completely around two-thirds of the dome and along 
the east side, and was found in place on the westside. It was therefore 
claimed as proven, that, whatever may have been the origin of this 
series of rocks, they are arranged in stratigraphic succession, with atop 
and bottom and at least one distinct and traceable horizon, and that the 
structure called "pitch'* was closely connected with the folding of the 
rocks. This is believed to be the first or almost the first succession 
definitely established by areal geology in the gneissic or Laurentian 
complex. 
16. Tertiary dislocations of the Atlantic coast of tltv United States. 
N. S. Shai.ek, Cambridge, Mass. The author has, in several papers, 
called attention to the evidence of mountain-building stresses in Ter- 
tiary and Cretaceous beds on the island of Martha's Vineyard. That 
these distortions were not produced by the shoving action of the last 
ice advance is shown by the fact that the folded strata were denuded 
into hills and valleys before the last glacial drift was deposited upon 
the island. Recently Mr. J. B. Woodworth, of the U. S. Geological 
Survey, examined the similar distortions of Block Island and found 
them closely to resemble those of Martha's Vineyard. While the age 
of the Block island beds is not yet clearly determined, they are in part, 
at least, Pleistocene, and have a topography newer than the distortions 
and older than the last glacial epoch. It is evident that the Atlantic 
coast has been the seat of considerable mountain-building since the 
Triassic period; the disturbances of theTriassic or Kinetic beds having 
taken place in the Jurassic period, or at lesst before the deposition of 
the Cretaceous beds. The disturbances described on Martha's Vine- 
yard and Block island, it seems clear, were not local. The action of 
similar forces has been traced southward by McGee and others along the 
coast. The occurrence of faults in the south and folds in the north 
finds its parallel in what we observe in the movements at the close of 
the Carboniferous period. In eastern Tennessee are mainly faults; in 
southwestern Virginia folds become more common, and thence north- 
wardly they increase in relative importance. These dislocations are 
thought by the author to indicate that the immediate coast region is 
the seat of mountain-making forces which have ceased to act in the 
Appalachian system. They afford additional evidence that a coast line 
is the seat of orogenic action. 
