
PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 497 
On 1°305 grammes,— 

Silica, . ‘ : -461 
From Alumina, . -005 
Dry (calculated). 
"466, = <351108 37°412 
Ferric Oxide, 12-925 13-542 
Ferrous Oxide, : *054 * 056 
Manganous Oxide, . "229 “24 
Lime, . : : peilyll anlye®) 
Magnesia, ' > ors 34° 764 
Water, . ; dosed iat 13 °594 
STM 99° 787 
Loses 4°545 per cent. of water in the bath; contained traces of potash and 
soda. 

Change by Hydration ; removal of Silica ; of the Iron ; of most of the Lime ; with 
abnormal and possibly direct augmentation of the Magnesia. 
Totagite. 
26. Serpentine is generally said to result from a change induced in augitic 
minerals, through the operation of what is called “the magnesian process;” 7.¢., 
the direct insertion of magnesia by magnesian waters, and the consequent 
increment of that material in the product. 
It is hardly necessary to show that such an operation, acting by itself, 
could never accomplish the necessary transformation. Pre-existent constituents 
have to be abstracted, and the mere abstraction of these will, of itself, by the 
consequent proportional incrementation of the non-abstracted magnesia, suffice 
to determine the required change. A simultaneous intrusion of magnesia is 
thus in no way required. 
In the substance now to be described, however, there is, as regards the 
Magnesia, an undue amount of incrementation,—under the supposition that 
serpentine was the substance aimed at, so to speak, in the change. Very 
unwillingly have I attached to a substance, palpably a product of pseudo- 
morphic conversion, a specific name. I do so to direct attention thereto, as a 
material which will have to be considered in the investigation of serpentinous 
formation. 
About 200 yards to the south-west of the ferryhouse at Totaig, in Ross- 
| shire, there occurs a substance in association with the blue malacolite already 
noticed, which Mr Dupceon and I at first imagined might be one of the sub- 
VOL. XXVIII. PART II, 6N 
