596 The American Naturalist. [July, 
Geological News, Cenozoic.—In studying the origin of Lake 
Cayuga, Mr. R. S. Tarr, has become a convert to the rock-basin theory 
of lake formation. In a paper recently published he shows that the 
preglacial tributaries to the Cayuga valley are rock enclosed and that 
their lowest points are above the present lake surface. This the 
author holds to be proof positive that Lake Cayuga is a rock-basin. 
If this be true, a similar course of reasoning would suggest that Lake 
Ontario is also a rock-basin, from the fact that the preglacial Cayuga 
River flowed north and was tributary to a river which drained 
Ontario, and whose channel was above the present surface of the lake. 
(Bull. Geol. Soc. Am., Vol. 5, 1894.) 
The recognition of the extension of the Pine Barren flora of New 
Jersey through Staten Island, Long Island, Nantucket, Southern 
Rhode Island, and Massachusetts, suggests to Mr. Arthur Hollick a 
theory of a continued existence of land connection between New Jersey 
and southeastern New England, by way of Long Island, during a suffi- 
cient time after the final recession of the glacier, for the pine barren 
flora to have spread and become established there. This theory would 
seem to be supported by the position and configuration of the chain of 
islands to the east of Long Island Sound, and by the geological history 
of this region. If Mr. Hollick’s views are correct Long Island, Block 
Island, Nantucket, Martha’s Vineyard, etc., as we now know them, 
have not been snbmerged since the final retreat of the glacier, and 
their separation into islands is a comparatively modern phenomenon 
due to erosion, and the depression of the costal plain. (Taans. New . 
York, Acad. Sci. Vol., XII, 1893.) 
A new theory of the origin of Drumlins has been advanced by Mr. 
Warren Upham, viz.; they are the result of the accumulation of 
englacial drift. The author offers the following explanation of the 
manner of the accumulation. The upper current of the thickened 
ice above the englacial bed of drift would move faster than the drift, 
which in like manner would outstrip the lower current of the ice in 
contact with the ground. Close to the glacial boundary the upper ice 
must have descended over the lower part. This differential and shear- 
ing movement gathered the stratum of englacial drift into the great 
lenticular masses or sometimes longer ridges of the drumlins, thinly 
underlain by ice and over-ridden by the upper ice flowing downward 
to the boundary and bringing with it the formerly higher part of the 
drift stratum to be added to these growing drift accumulations. The 
courses of the glacial currents are not determined by the topography 
of the underlying land, but by the contour of the ice surface. (Pro- 
ceeds. Boston, Soc. Nat. Hist., Vol. XXVI, 1893.) 
SEE P OR 
