288 



THE GEOLOGIST. 



formed along this line, and present a very remarkable ap- 

 pearance^ from their perfect aridit}^, their elevation above the 

 lake, and the generally uniform level of their summits ; they 

 appear to rest upon more compact beds of clay and gravel, 

 and have evidently been washed up by the waves and driven 

 landward by the wind. Tempests of sand are thus formed, 

 which spread inland, burying the tallest trees, and carrying 

 desolation in their track. The same wind and wave action 

 is described by the author as taking place on some parts of 

 the coasts of Huron and Michigan ; dunes are first formed, 

 and then spread inland, bearing sterility over thousands of 

 acres, formerly fertile and well wooded. Another efi'ect pro- 

 duced by this drifted sand, is to occasion the formation of 

 pools and morasses along its shifting boundary line, thus 

 injuring other large tracks of country. The recent date of 

 this formation is often shown by buried trees and freshwater 

 shells found at great depths in excavating, or exposed by 

 irruptions of the waves. M. Schoolcraft describes other 

 arenaceous deposits forming broad sandy belts, bordering the 

 lakes, and supporting a light growth of pines, poplar and 

 birch ; these he considers due to a similar action, at an 

 earlier period, when the water of the lakes stood at a higher 

 level and occupied a wider area, a condition which is further 

 indicated by the occurrence of wide lacustrine deposits in 

 the same neighbourhood. On the shores of the lakes there 

 sometimes occurs a deposit of iron sand, often a foot in 

 thickness, formed from the magnetic oxide of iron, which 

 exists abundantly in the sandstones, and is set free by the 

 action of the waves in comminuting the rocks. 



Mr. Philips referred to similar accounts, given by Lieut. 

 Nelson, of the influence of the wind in the Bermudas, in 

 transporting sand, shells, and corals inland ; he considered 

 it highly probable, that many of the beds of new red sand- 

 stone, overlying those in which the cheirotherium footsteps 



