246 On the Alpine Glacier, fyc. Theories. £No. 159. 



Outside of this so-called tract of diluvium, Captain Herbert men- 

 tions a red earthy marl, with patches of sand and a blue clay, the 

 relations of which with the unstratified gravels should be minutely 

 described, and every search made in them for fossils. The black and 

 blue clays may possibly bear some affinity to the regur in mineral 

 composition. 



I have not been able to consult Professor Royle's admirable work 

 on the Himmalaya, or Dr. M'Clelland's valuable geological observa- 

 tions, in the remote part of India where I now write; but cannot 

 conclude this list of Desiderata without strongly recommending their 

 perusal to the observer travelling through or located in the interesting 

 districts of which they treat. 



