PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 555 
minerals acts as a bar to their paragenetic occurrence. ‘The subjoined 
columns exhibit the information which is to be derived from the specimens 
that have been analysed. 


In Juxtaposition. Apart. 
Shinness, . . Malacolite and Actynolite. | Totaig, . : . Malacolite. 
Glen Tilt, . . Malacolite and Tremolite. Beinnegapple, . . Augite. 
Tiree, . ; . Sahlite and Actynolite. Alltcailleach, . . Malacolite. 
Eslie, . ; . Sahlite and Actynolite. Ben Chourn, . . Sahlite. 
Balta, , . Augite and Hornblende. Pinbain, . : . Diallage. 
Elie, . : . Augite and Hornblende. Tarfside, . : . Sahlite. 
Portsoy, . . Augite and Asbestus. Loch Tay, : . Sahlite. 
Glen Gairn, . Sahlite and Actynolite. Cuchullins, . . Augite. 
Crathie, .- . Sahlite and A ctynolite. rum, 9 ; . Augite. 
Colafirth, . . Sahlite and Actynolite. John O’ Groat, . Augite. 
Glen Beg, . . Augite and Actynolite. 7 
Craig Lui, . . Augite and Actynolite. Coyle, . : . Actynolite. 
Fetlar, . : . Hornblende. 
Nudista, . : . Actynolite. 
Urquhart, : . Actynolite. 
rnin) Fe : . Actynolite. 
Portsoy, . : . Hornblende. 
Glenbucket, . . Hornblende. 
Enesay Island, . Actynolite. 

This tabulation does not point to any marked non-consorting of the one 
mineral with the other. The very frequent apparently solitary occurrence of 
asbestus and other fibrous varieties of hornblende in serpentine rocks proves 
nothing, as here these rocks may have been formed from augite, the less 
alterable hornblendic mineral being left unchanged. 

One other point calls for brief notice,—the question as to augite being a 
voleanic or fusion-form of hornblende. It will be seen above that both of the 
minerals occur in granular limestones; these afford very distinct evidence of 
the operation of great heat. 
Again, it will be observed that both occur together in the basalts and dykes 
of Elie and Kinkell; in these the one mineral—the augite—has undergone 
fusion ; while the other—the more fusible—appears unchanged. This circum- 
stance becomes a strong argument in favour of the latter having been formed 
Mm situ,—i.e., after the eruption and cooling of the containing rock,—an exfil- 
tration product in fact. 
Here it may be the case that the fused augite has at one time been formed 
from hornblende, but the two could not here have been erupted together; so 
| that no direct evidence is to be gleaned from this apparent paragenesis in space, 
which palpably was not a paragenesis in time. 
