SALMON — OX THE FOEMATIOX OF ORE-VEINS 



355 



sion of the creature through, the water, the niediiim in which it is 

 destined to pass its existence. 



From the fish we pass upwards to the Reptiles, in which we have 

 a considerable advance of organization, and the first decided traces 

 of fore and hind limbs or legs for terrestrial or amphibious locomo- 

 tion. The heart of reptiles has but one ventricle, and the circulation 

 of their blood is sluggish and slow ; and indeed then* whole organ- 

 ization is far inferior to the animals of the next and highest class of 

 animals, the Mammalia. 



In these last the blood is warm ; the heart is possessed of amides 

 and ventricles ; the circulation free and rapid ; and the internal 

 skeleton of the highest perfection of development. At the top of the 

 class stands man, the most intellectual and most highly organized of 

 all created things. 



GEN'EKAL CONSIDERATIONS ON THE FOR^^IATION OF 



ORE-VEINS. 



(Translated from the German of Professor Bekxhard Cotta, of 

 Freiberg, vjitli an Introductory Notice on the Study of Mineral 

 Veins and Metcdliferous Dej^osits, hy H. C. Salmon, Esq., Plymouth.) 



I propose, from time to time, in the pages of this magazine, to 

 bring before geologists and geological students translations or 

 abstracts of some of the most authoritative memoirs of foreigTi 

 geologists on the subject of mineral veins and metalliferous deposits. 



Notwithstanding the great commercial value of the metallic mines 

 of the United Kingdom, the subject of mineral veins and metal- 

 liferous deposits has not, of late years, occupied the serious attention 

 of many men of recognized scientific position in this coimtry : the late 

 Sir Hemy de la Beche, Mr. W. Jory Hemvood, and ]\Ir. Waring-ton 

 Smyth are those best known. The strong distaste which im- 

 doubtedly exists to inquiries in this field of geology is due to many 

 causes which it would be out of place to discuss here. I may 

 nevertheless be permitted to say that, however just this feeling may 



