206 REVIEWS 



the ice contain water, and are thought to be due to the closing of 

 water-filled crevasses. The presence of water-filled cavities within the 

 ice of glaciers shows that the winter's cold does not penetrate far below 

 the surface. 



An ingenious arrangement consisting of two sticks placed in diverg- 

 ing auger holes and inclined toward each other and securely bound 

 together with wire at the surface of the ice, gave accurate measures of 

 the rate of surface melting. In general, the waste on the surface of 

 Muir glacier was two inches per day. Soundings in Muir inlet, which 

 also furnished water samples from various depths, measurements of 

 temperatures for the surface to the bottom, and samples of the bottom, 

 gave a series of instructive records, which are briefly discussed. Tidal 

 observations made in Tidal inlet, a small iiordlike bay, five miles 

 west of the head of Muir inlet, furnished data for establishing a per- 

 manent bench mark on the shore by means of which changes of level 

 of the land can be measured. It is hoped that future travelers will 

 repeat these measurements and also profit by the instructions which 

 are given for photographing the extremities of the tide-water glaciers, 

 so that a record of their variations may be obtained. 



The report before us contains the records of the only systematic 

 survey that has been made of any of the Alaskan glaciers, and is of 

 special value on account of the painstaking accuracy that characterizes 

 the work. A splendid beginning has been made in the study of the 

 great system of ice drainage that pours into Glacier Bay. It is to be 

 hoped that other students of glacial phenomena, having before them 

 this example of what can be accomplished during a summer vacation, 

 will continue the work and explore the unknown regions surrounding 

 the area represented in Professor Reid's map on every side. 



Israel C. Russell. 



Water Resources of Illinois. By Frank Leverett ; Seventeenth 

 Annual Report U. S. Geological Survey, pp. 695-849, Wash- 

 ington, 1896. 



This paper contains much of distinct geological interest, as may 

 well go without saying, both on account of the intimate connection of 

 hydrology with geology, and, in especial, because of the author's 

 thorough study of the Pleistocene formations of the state. The effect 

 of the drift upon topography and drainage is set forth with consider- 

 able detail. On the newer drift, within the Shelbyville moraine. 



