238 Professor Forbes on the Leading Phenomena of Glaciers, 



"We have also considered glaciers generally as of three kinds, 

 which, having a common structure, yet exhibit it in different 

 forms or modifications. These three glacier forms may be 

 termed the canal-shaped^ the oval, and the glaciers of the se^ 

 cond order. The annexed figures (one of which has been 

 already used) shew by views with ideal sections of such gla- 



ciers, the manner in which the structural surfaces traverse the 

 mass of the ice. The first figure shews the conoidal struc- 

 ture of a glacier of the oval kind. The second shews this 



