Glacial Movements in Sweden. — Wright. 271 
by the sharp line which separates the blue from the yellow 
till. 
But the most important discoveries bearing upon this 
point were found at Tapplelargo, twelve miles east from 
Malmo. Here is an area of several acres covered with an 
overwash deposit from the moraine, which is a mile or 
more to the south. In a stratum of clay, about seven feet 
thick, many species of shells and plants are found, indicating 
peculiar conditions which can be accounted for only by sup- 
posing that during the final melting away of the ice the 
summers became very warm, so as to allow temperate 
species to flourish close up to the ice-front, thus allowing 
them to mingle with arctic or subarctic species. 
It is evident from inspection of the stratum that these 
species lived and were deposited contemporaneously, and 
not by an advance of the ice after an interglacial period. 
This would seem to meet the case of comingling of tem- 
perate and subarctic species which Coleman has described 
in the vicinity of Toronto, and so it will greatly simplify 
our interpretation of glacial phenomena in the northern 
United States and Canada. 
BOLSON PLAINS OF THE SOUTHWEST. 
By W. G. Tight, Albuquerque, N. M. 
There seems to be a very decided tendency on the part 
of students in physiographic geology to enlarge upon the 
conceptions of topographic types, as they are originally 
described, and in the subsequent study of the topographic 
features of any particular section, to describe those features 
in terms of the modified conception of the type forms. 
As a result there develops a very confused idea in the 
minds of workers concerning the true type, and with that 
misconception in mind the correct interpretation of any par- 
ticular region becomes doubtful, and the description of that 
region almost wholly unintelligible, giving to the student 
who has access to the literature alone, a radical misconcep- 
tion of the true topographic conditions. 
As an example of my meaning the term "peneplain" may 
be taken. It would be interesting to know how many times 
