880 THE JOURNAL OF GEOLOGY. 
it is possible that the importance of topography in its bearing on 
this question, has been overrated. But if the conclusion be cor- 
rect, it will be seen that it is not without bearing on the question 
of the cause of the glacial period. Of related import is the fact 
that the conditions for glaciation on the Greenland coast seem to 
be much better today in latitude 74° to 76°, than in latitude 
76° to 79°. It is not merely that there are more and larger 
glaciers in the former region, descending to lower levels —for all 
this might be the result of topography —but the snow line itself 
is 1000 to 1200 feet lower in latitude 76° than in latitude 78°. 
Evidence concerning past glaciations, drawn from nature of rock 
surfaces.—The first stop on the coast of Greenland was at Hol- 
stensborg, latitude 67°. The rock in this region is gneiss, 
which is much more distinctly and regularly bedded than 
gneissic formations usually are. From a distance, the rock has 
the appearance of being distinctly stratified, the dip being tol- 
erably constant. So strong was this impression that it was diffi- 
cult at a distance to avoid the conclusion that the rock was 
sedimentary. The general dip is to the northward, at an angle of 
60° to 75°. On the land, the gneiss is seen to be affected to 
some extent by dikes of granite, but they are not sufficiently 
numerous to obscure the general regularity of structure. Its 
surface has undergone a notable degree of decomposition since 
glaciation. Stria were not seen, nor did the rock surface show the 
polishing which glacial action produces. All these details were 
gone, although hills having the form of roches moutonnées were ot 
common occurrence, and glacial drift was not wanting. This con- 
dition of things suggested that the lapse of time since the depart- 
ure of the ice has been considerable. This is the more significant 
since it is in striking contrast with the condition of things along 
some other parts of the coast. It is clear that the cursory 
examination of the surface of a small area does not afford a safe 
basis for generalization. Nevertheless it is worthy of note that 
the amount of change undergone by the surface of the gneiss 
about Holstensborg since the ice abandoned it, appears to be 
greater than the average amount undergone by similar forma- 
