420 



SCIENCE. 



[Vol. IV., No. 91. 



produce a most characteristic landscape. Fig. 8 gives As to origin, there is a general agreement now, among 

 the view south-east and south-west from one of the the observers who have studied them, that their pres- 



feb^.,. 



'M 



Fig. 6. 



hills at the town of Clyde, on the New- York central ent form is an immediate result of ice-action ; but 

 railroad ; and fig. 9 illustrates some of their common just how they were constructed is still an open ques- 





Fig. 7. 



varieties of form. Farther west they are described tion. The theory that seems most satisfactory is that 

 only in Wisconsin, where they are sometimes circular which compares them to sand-banks in rivers, and 



Fig. 8. 



Fig. 



and symmetrical, as in fig. 10, from Professor Cham- thus considers them the result of gradual local accu- 

 berlin's geological report. mulationof drift beneath the old glacial sheet, where 



Fig. 10. 



From this brief survey, it may be seen that drum- more material was brought than could be carried 



lins have both a wide and an irregular distribution, away. The author will be pleased to learn of other 



and, further, that much more observation and map- localities for drumlins than those here mentioned, 

 ping are required before we shall acquire a satisfactory W. M. Davis. 



•explanation of their seemingly accidental occurrence. Cambridge, Mass. 



