*214 
SOUTH COAST OF THE CRIMEA. 
c vf P ’ perhaps ascribed to the iron in their composition. 
— > Where the oxide of iron is found to be a predo- 
minant feature in mineral strata, veins, fissures, 
and separations of the substance, may generally 
be noticed : and, vice versa, if the external 
figure of the mass in aluminous rocks be evidently 
prismatic, there is reason to apprehend the pre- 
sence of this metal, in a more than usual 
proportion. These observations merit the con- 
sideration of more scientific geologists. In 
addition to the facts necessary for their con- 
firmation, it may be mentioned, that the 
phenomena of the Giant's Causeway, upon the 
north coast of Ireland; of the pillars of trap at 
Halleberg and Hunneberg in Sweden, and at the 
Lake Bolsenna in Italy, and many other places ; 
are only regular in their prismatic forms where 
they have been long exposed to the action of 
the atmosphere. When the exterior surface has 
been thrown down, the interior of the mass 
exhibits only an appearance of incipient de- 
composition. 
iiiouT The supposed transitions, or the passages, (as 
they are termed by some French and by many 
German mineralogists) from one mineral species 
to another, might meet with at least a semblance 
of reality upon this coast : so insensible is the 
