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PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 305 
throughout the general mass of some marbles (LEDBEG, SUTHERLAND, ¢@.g.) 
would seem to indicate actual fusion. 
The second—That it has not yet been shown that there is the necessity for 
such concentration. | 
The high specific heat of the matrix is, in the present case at least, amply 
sufficient ; no one of the minerals found in the above localities possessing so 
large an amount of heat as - 264 — that of limestone. 
That of the following is known— 
Blaor : : F -19 
Apatite, ; : : a lee 
Tetrahedrite, . : ; : ; -192 
Actynolite, . : 204 
Augite, . , : : * 194 
Diopside, ' 4 “ALG 
Pyrrhotite, . : ; : °16 
Molybdenite, . : ‘ : : -102 
It is a somewhat significant fact that limestone has a specific heat superior to 
that of any other rock mass; we speak of mollusks and crustaceans as “cold 
blooded,”—though it is believed that they have a temperature somewhat higher 
than that of the medium in which they live ;—but the calcareous matter which 
they have secreted from solution in that medium, for the defence of their soft 
parts, is deposited and arranged with an organic and non-crystalline structure, 
and consequently has had conferred upon it the high specific heat of the 
amorphous state; and so the long buried skeletons of these organisms are 
abiding store-houses of heat, until called upon to yield up their surplus store, 
and thus become the active agents of future change. 

In illustration of the foregoing speculation, a brief sketch may now be 
appended of the localities in Scotland where limestones of the age above referred 
to occur. 
Although there are many localities where metamorphic rocks contain 
calcareous beds, yet their continuity and connections can nowhere so easily be 
made out as in the counties of Banff, Aberdeen, and the north of Perth. 
In this district the general trend of the outcrop is from N.N.E. to 8.S.W., 
the dip, usually at a high angle, being to the E.S.E. The lowest member of 
the series which includes calcareous beds is an argillaceous mica-schist ; this is 
succeeded, to the east, by a highly metamorphosed quartzite of a pinkish tint, 
the dip of which, in its northern reaches at least, is somewhat more southerly 
than that normal to the series. Eastward of the quartzite the characteristic 
“omnarled gneiss” of Scotland supervenes,—rolling over the country in repeated 
