650 REVIEWS 
familiar to the readers of this magazine. The results of his pro- 
longed investigations are here brought together, summed up and 
illustrated with a beauty and force which make the paper a monu- 
mental contribution to archeology and anthropic geology. (S. 
Glacial Observations in the Umanak District, Greenland. By PRo- 
FESSOR GrEorGE H. Barton. Report B of the Scientific Work 
of the Boston Party on the Sixth Peary Expedition to Greenland. 
The paper embraces the observations made by Professor Barton on 
the border of the inland ice in the vicinity of Umanak fiord and upon 
the large Karajak, Itivdliarsuk and several small valley glaciers. Mr. 
Barton found the border of the ice usually nearly vertical to the 
height of ten to forty feet. The surface in the vicinity of the margin 
was covered with dust holes ranging in diameter from a fraction of an 
inch up to at least three feet, with an average depth of about two feet. 
Except the dust found in these holes no detritus occurs on the sur- 
face of the inland ice. The largest surface stream found flowed in a 
channel having a width of twenty feet with a depth of fifteen feet to 
the surface of the water which was about five feet in depth. At the 
point observed this river was flowing directly toward the interior with 
a velocity of three or four miles an hour. The average gradient of 
the surface measured on the Karajak glacier was found to be 1 in 52. 
Professor Barton observed that the overhanging marginal faces were in 
many cases apparently due toashearing motion of the upper layers over 
the lower. ‘‘This was indicated quite strongly in one instance, where 
a layer projecting slightly beyond the ones above had caught a little 
detritus as it rolled down. ‘This same ledge continued from the 
slightly inclined face along a portion of the overhanging face, and 
here still the detritus remained which had been caught in its descent 
before the shearing motion had changed this part of the face to an 
overhanging one. A cavern presented a chance for a study of the 
material forming the layer upon which the detritus had lodged, and 
also for several feet above, showing them to be free from detritus and 
consequently that the detritus could only have come from the upper 
surface and caught upon the shelf, while the face was inclined, and 
that its present overhanging form was due to the shearing motion in 
the upper portion of the ice’’—a very important observation. 
Professor Barton gives interesting illustrations of the hold of the 
