280 The American Geologist. April, 1892 
for when broken into there are few places that do not show signs of 
stratification especially along old lines of drainage. On the extreme 
west end of the island where the flood of waters was great, nearly the 
whole of the moraini¢ material is affected by it. The old subglacial 
channels are innumerable along the whole extent of the terminal moraine 
and the marginal kames and kame deltas were formed by the icy cur- 
rents that issued from the front of the ice-sheet. Where the currents 
were strong the moraine is correspondingly broken, and the kames in 
front become more prominent as may be seen in the vicinity of Fort 
Hamilton and Greenwood cemetery. These marginal kames extend out 
for some distance from the ridge proper, and it is rather difficult to de- 
termine their exact southern limit, except by the slight covering of un- 
modified drift. I am inclined to think that the ice-sheet did not end 
with the so-called terminal moraine, for even the kame deltas that extend 
southward to the ocean are covered with a yellowish sandy clay, very 
much like the englacial drift referred to by Mr. Upham. 
It is true, that the boulder line seems to end with the marginal kames, 
yet there is such a blending of the two, that no distinct line can be 
drawn between the marginal kames and kame deltas. The unmodified 
boulder drift covering the former would show, however, that the so- 
called englacial till extended farther southward than the subglacial till, 
in its unmodified form. It has seemed to the writer that these southern 
kames could not have been formed without the aid of an ice-sheet, and it 
may be that a study of this so-called englacial drift will lead to the 
solution of the problem, for this superficial deposit covering the plains 
on the south side of Long Island has never been satisfactorily explained. 
I made mention of it in my pamphlet on the formation of Long Island, 
published in 1885 and was unableto account for its origin. It still re- 
mains a puzzle, but I think we are getting nearer an explanation. 
Eastport, L. I., Jan., 27, 1892. JOHN Bryson. 
PERSONAL AND SCIENTIFIC NEWS. 
Proressor G. FREDERICK Wricut delivered a series of ten 
lectures in Boston during February and March, on ‘The Antiquity 
and Origin of the Human Race,” as one of the free Lowell In- 
stitute courses. The bearing of geology on this subject centers 
in the question, How long ago was the Glacial period? Professor 
Wright in reply accepts the conclusions of Prestwich, Gilbert, N. 
H. Winchell, and others, based on the amount of postglacial 
erosion of waterfalls, and on other evidence, which from many in- 
dependent observations, computations, and estimates, give 7,000 
to 10,000 years, more or less, as the time since the great ice- 
sheets of North America and Europe were melted away. Man 
was contemporaneous with the latest and maximum extension of 
the ice on both continents, as is known by his stone implements 
