Clifton Collef/e Scle.ni\jic Society. 85 



of the sea, as in the Bays of Norwick, Haroldswick, and Balta. The 

 diallage is hard, good instances of which property are the Islands of 

 Balta and Hunie. 



A few words may be said with regard to the form of hill peculiar 

 to the different formations. The ser]3entine hills of Crncifield, Mica- 

 ford, and Keen, have a smooth, round appearance, without any sharp 

 and rugged peaks. This is due to denudation, weathering, and solu- 

 bility. Heog's Hills, nevertheless, terminate in abrupt peaks, which 

 I think is due to a hard intrusive rock running up through them. 

 The diallao-e hills are somewhat broken, but the gneiss ridges on the 



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 practice ; and these are by no moans solitary instances of the age of 

 its inhabitants. 



I was unable to ascertain the exact amoimt of rainfall, but it is 

 considerable. A day, however, seldom continues rainy throughout, 

 the showers being short and sudden. 



Geology. — The rocks, now under our notice, may all be classed as 

 metamorphic, and include gneiss, micaceous, talcose and chlorite 

 schists, primitive crystalline limestone, serpentine and diallage, 

 together with hypersthene, hornblende, slate, etc. The accompanying 

 map shews the order of succession. There are many interesting 

 topics here for the chemical geologist to discuss : as to whether the 

 serpentine is a metamorphosed limestone, and the relation of such 

 minerals as chromate of iron, amianthus, and asbestos, to their con- 

 taining rocks. 



The Gneiss occupies the entire length of the western side of the 

 island, from Hermaness to Bellemont, and, as before mentioned, forms 



