~224 The American Geologist. March, 1894 
Many of the fragments of quartz have been secondarily enlarged by one 
or two zones of quartz of the same orientation. Sometimes the zone 
of enlargement roughly approximates a crystal outline. Where there 
are two zones of enlargement there is a zone of granular quartz between 
them. The fragments of quartz appear to be of granitic origin. The 
matrix is of chalcedony, sometimes arranged in one or two rather 
coarsely fibrous, incomplete, concentric shells around the spherules, 
sometimes in very minute fibers without apparent orientation, and 
sometimes in very small spherulites. Granular quartz also occurs in 
the matrix. No organic remains were observed. The origin of the rock 
appears to have been a clear quartz sand impregnated by hot siliceous 
waters. Another siliceous oolite said to be from the Tertiary of New 
Jersey was described. In this the spherules of chalcedony are very ir- 
regular in size and distribution. Many of them are 6pherulites without 
an apparent nucleus, while others have grains of quartz in their centers. 
The paper was illustrated by a drawing of the first oolite between 
crossed nicols, and a photo-micrograph of the second in ordinary light. 
:>'.). Channels on drumlins, canned by erosion of glacial streams. 
George H.Barton, Boston, Mass. (Read by title.) Under the di- 
rection of Prof. N. S. Shaler, for the U. S. Geological Survey, nearly 
eighteen hundred drumlins have been studied in Massachusetts and 
along the southern edge of New Hampshire. Of postglacial erosion 
there is but little indication, each hill remaining nearly as symmetrical 
and perfect as it first appeared when finally left uncovered by the re- 
treat of the ice-sheet. Cases of erosion produced in the smooth, flow- 
ing outlines of these lenticular masses of till before the ice-sheet had 
entirely uncovered them are abundant, more than one hundred having 
been observed. These consist of channels winding down the southern 
or southeastern slopes of the drumlins. In size they vary from merely 
incipient depressions to those that are from sixty to one hundred feet 
in depth. In typical drumlins, having the longer axis parallel with the 
motion of the ice-sheet, these channels are nearly always parallel with 
the axis and often coincident with it, cutting directly along the sum- 
mit of the ridge as it slopes southward. In the more complex masses 
of till, which often extend in their longer direction nearly at right 
angles to the glacial motion, they cut down the southern slopes with a 
direction usually approximately parallel to that of the axes of neigh- 
boring typical drumlins. With very few exceptions, there is no cut- 
ting down the northern slopes of either the typical drumlins or of the 
complex groups. In many cases the cutting begins north of the sum- 
mit but passes directly through it with the bottom of the channel 
sloping southward continuously from its most northern point. 
In origin these channels seem to have nothing in common with the 
more or less deeply cut valleys between the separate summits of one 
complex mass. The drumlin contour seems to have been perfectly 
formed previous to the cutting of the channels. In a few cases direct 
linear connection is shown between the channels on several separate 
drumlins, and then usually remnants of eskers occupy the low lands 
between. This would seem to indicate that the same stream that de- 
posited the esker performed the cutting of the channels. During the 
early part of the work Prof. Shaler called attention to a channel upon 
Forbes hill, in Quincy, and suggested the above reason for its origin. 
Lying upon the southern slopes, with little or no indications of existence 
on the northern, they must have been formed when the ice had been 
melted from the south but still lay banked against the northern slopes, 
by superglacial or englacial streams, which to the northward flowed 
over icy beds and here were discharged from the front of the ice to 
plow their way down the southern slopes until they reached the lower 
levels or plunged into standing sheets of water, as they did in many 
instances. 
