672 REVIEWS 



slippings along the same fault planes or that the elastic waves have been 

 transmitted mainly along these planes. Adjustments of smaller amplitude 

 have occurred along other planes but in no case is there any evident relation 

 to an epicenter. H. H. 



Drumlins of Central Western New York. By H. L. Fairchild. 

 New York State Museum, Bulletin iii; 76 pp., 20 pL, map. 

 Albany, 1907. 

 New York possesses the most remarkable group of drumhns in the 

 world, and this bulletin, with its excellently prepared maps, photographs, 

 and descriptive matter, will be a welcome addition to a glaciologist's library. 

 The distribution of the New York drumlins shows that they were formed 

 during the latest phase of glaciation by the spreading of the ice from the 

 Ontario basin. A sliding movement of the lower ice caused by a horizontal 

 thrust from behind seems to be essential to drumlin formation, though the 

 quality, position, and volume of the drift material, and the degree of the 

 vertical pressure and of the mobility of the ice are also factors. The shales 

 of central New York furnished a peculiarly adhesive drift from which the 

 drumlins were constructed by a plastering-on process. These masses of 

 drift were thus given their peculiar shapes by the rubbing action of the ice 

 movement during the final stages of diminished pressure and lagging flow. 

 The presence of open spaces in the midst of strongly drumlinized areas is 

 difficult of explanation. In some cases depressions may have lain at such 

 a low level that a plane of shearing was formed in the ice above them so as 

 to leave a mass of stagnant ice beneath. An earlier ice invasion may have 

 localized the drift of the ground moraine that was to be shaped into drum- 

 lins by the next invasion; but no drumlin was observed, the internal structure 

 of which revealed a direct derivation from terminal moraine material. 



H. H. 



Geology and Water Resources of the Bighorn Basin, Wyoming. By 



Cassius A. Fisher. U. S. Geological Survey, Professional 



Paper, No. 53; 51 pp., 20 pL, map. Washington, 1906. 



The region described comprises about 8,500 square miles, situated 



mainly in Bighorn County in northwestern Wyoming. The most striking 



topographic feature is a broad structural valley bounded on nearly all sides 



by high mountain ranges and containing in its interior high badland slopes. 



The amount of water in the principal streams varies greatly with the season 



of the year, being greatest in early summer; but irrigation has been prac- 



