PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 507 
Insoluble silica, 1-095; there was no fluorine. It is most strange that a 
substance which seems the very type of purity and simplicity of constitution, 
so far as appearance goes, should have so complex a composition. 
I strongly incline to the opinion that this is an augitic tremolite, but am 
unwilling further to diminish the specimen for the determination of the point. 
7. From the most north-easterly of the limestone quarries of Milltown, 
Glen Urquhart. | 
This variety, being highly aluminous, probably should not be placed here ; 
but where better to place it I know not, for in form it is distinctly tremolite. 
It occurs in crystals of one-fourth of an inch in size ; these are of a somewhat 
bright yellow colour; they are imbedded promiscuously in the granular 
limestone, and are so closely associated with talc that their separation there- 
‘from was very tedious and difficult. The colour was not due to weathering ; 
as crystals dissolved out of the mass of the lime had as high a colour as those 
lying upon the exposed surfaces ; and the centres of the crystals also were as 
highly coloured as were the surfaces. 
They were analysed in a hitherto vain attempt to find out what substance 
it is which has been called “chondrodite from Loch Ness.”* The single 
“specimen to which that name was applied is now in the British Museum (I 
believe it to be yellow serpentine): it is imbedded in a limestone which in 
no way resembles the Urquhart lime. Were it not that arsenical pyrites is 
to be seen in this specimen, [ should consider it as coming from Glen Elg. 
Of this tremolite, 1-3 grammes yielded— 
Silica, ; : : 732 
From Alumina, . Ours 
745 == are SOME 
Alumina, . 5 5 5 SAG 
Ferric Oxide, 1-082 
Ferrous Oxide, . 3° 229 
Manganous Oxide, . : 307 
Lime, ; ; : ed 2S oul 
Magnesia, : : . 16°615 
Water, with Fluorine, ie Es) 
LOOBOGT 
Insoluble silica, 2°147 per cent. It was found impossible absolutely to 
separate the talc; the amount present could not, however, have amounted to 
more than the hundredth part. 
* See Gree and Lerrsom. 
