Geology and Paleontology. 345 
obscured to the west and south by drift, and to the north and east 
absent or rarely seen, although the crystalline rocks are commonly 
rounded or very rarely polished, an absence that can only in part 
be accounted for by subsequent atmospheric erosion. About the 
St. Lawrence and Lake Ontario the striations are to the southwest 
or west. Between the Ottawa River and Georgian Bay there is a 
high prominence, which divided the drift-bearing currents. But 
north of Lake Huron’the glaciation is very strongly marked, and 
the direction is to the southwest, with very rare local variations. 
All the lobes of glaciation about the lakes, from Superior to the 
Ottawa Valley, radiate backward to the broad and open but low 
basin of James (Hudson) Bay. The watershed between the lakes 
and Hudson’s Bay during the epoch of the formation of the drift 
was several hundred feet lower than now—which is about 1600 
eet at present—as shown by the differential elevation of the 
beaches. For this conflicting phenomena of the drift no explana- 
tion was offered, but rather sought for. ‘ 
Some remarks upon the paper were offered by Mr. Gilbert, who 
had observed the slight amount of erosion in the Ottawa Valley ; 
but he thought that generalized explanations of the drift were very 
‘often contratlictory when applied to special regions, and that our 
knowledge of the phenomena would not at present give a satisfac- 
tory explanation. 
GLYPTODON FROM TEexas.—In the Proceedings of the Philo- 
‘Sophical Society for 1884, p. 2, I recorded the discovery of a 
Species of Glyptodon in the valley of Mexico by Professor Castillo, 
Which was at the time the most northern locality at which the genus 
iad been discovered. I can now announce its discovery within the 
limits of the United States, in Nueces Co., Southern Texas, by my 
friend, Mr. William Taylor, in the beds which have yielded 
Equus crenidens Cope and E. barcenæi Cope, both species of the 
valley of Mexico. 
The present species is represented but by a single segment of the 
"carapace, but as the sculpture of these elements is very character- 
istic, and as my means of comparison are very large, since my 
Pampean collection embraces a majority of the species, I venture to 
‘describe it. It belongs to the group in the genus represented by 
i pet te Owen, and G. oweni Nodot. It is a species of large 
Size, with very thick carapace, and with the circumferential areas of 
the rosette but little smaller than the central one. The former are 
regularly pentagonal, the latter regularly hexagonal, and they are 
— by well-defined grooves. foramina very few. 
The surface of the areas is flat and in one plane. The texture of 
the median area differs from those round it in being im 
with numerous small, closely-placed foramen-like fosse. Its sur- 
face supports no tuberosities. The circumferential areas are marked 
