REVIEWS 103 



" Untersuchung iiber Gletscherstruktur und Gletscherbewegung." 

 By Hans Phillip. Geologische Rundschau, Bd. 5, Heft 3, 

 Marz, 1914. Pp. 6. 



The author has just completed observations on the arctic glaciers 

 of Spitzbergen and the valley glaciers of the Alps and states he finds 

 "banding a specific property of all ice-masses moving of themselves." 

 Opportunity to observe the structure of these bands on the vertical 

 faces at end and sides of a number of glaciers indicates a conformability 

 of the bands to the shape of the valley containing the glacier; they are 

 hence "trough-shaped." The bands are not formed by pressure analo- 

 gous to that which forms slaty cleavage in rocks, for they are alternately 

 of blue, compact ice and white, air-filled ice. Neither are they the 

 original bedding of the snow-field for in certain instances this is seen in 

 conjunction with the longitudinal banding. The bands are separated 

 by deep cracks (Rissen) about 2 cm. wide and traceable for as much as 

 100 m. The cracks are from one-half to two meters apart and, like 

 the bands, are trough-shaped. Careful measurement has shown a 

 differential movement of the bands separated by the cracks. On the 

 average this differential movement was 20 cm. in six weeks, with the 

 greatest movement a short distance below the surface. 



The writer concludes that the trough-shaped cracks between the 

 bands indicate a differential movement of the bands. The movement 

 along the cracks produces the white, air-filled bands by crushing the 

 ice fragments. This conception of glacier movement is to be dis- 

 tinguished from the notion of movement by means of gliding planes 



(Gleitflache) within the ice crystals. 



R. C. M. 



Conies, with Special Reference to Those of the Campsie Fells. By 



J. W. Gregory. Trans. Geol. Soc. Glasgow, XV, Pt. I, 



1912-13. Pp. 15, plates 2, figs. 4. 



"Corries" (Scottish equivalent for "cirque," "Kar") are rounded 



amphitheater-shaped depressions with steep, smooth walls and fiat 



floors. They have been explained (1) by glacial plucking at the head of 



small local glaciers during the last stage in the glaciation of a district, 



(2) by the action of a series of confluent waterfalls, each of which under- 

 cuts the rocks at its foot and leads to the erosion of a vertical cliff, and 



(3) by the alternate action of frost and thawing which disrupts the walls 

 of the valley, while the floor is essentially protected from erosion by a 



