374 MR. CLOUGH AND DK. POLLAED ON SPINEL [Aug. 1899^ 



mentions that corundum is supposed to have been formerly found 

 in Tiree, but he says that no specimens of the corundum have been 

 produced, and he evidently doubts whether the supposition is correct. 

 Prof. Heddle^ has described a blue sapphire, about J^ inch in 

 diameter ; this he found embedded in a red andalusite, vs^hich rarely 

 occurs in quartzose veins, in the schist of Clashmaree Hill, in 

 Glen Clova (Inverness-shire). 



The geological survey of the Glenelg district was commenced in 

 the summer of 1897, and a short account of the work accomplished 

 in that year has already been published.^ Much has still to be 

 done before the survey of the district is completed, and our remarks 

 will only lightly touch some of the interesting problems which the 

 district presents to the geologist for solution. 



There are in some places three or four different bands of lime- 

 stone .and one of these bands, a short distance east of Beinn Fhada 

 Ros»-shire 6-inch maps 123 & 127), is as much as 150 yards wide. 

 The rocks of the district are, however, greatly folded, generally into- 

 isoclinal folds with both limbs hading east-south-eastward, and the 

 limestone-bands are all so much alike in lithological character that 

 it seems possible that they may belong to one bed which has been 

 repeated by folding. The limestones occur in, or occasionally at the 

 Bide of, a series of banded gneisses, micaceous gneisses or mica- 

 schists, hornblende-schists and eclogite-rocks.^ "Where there are no 

 faults, this series lies about 1 mile east-south-east of the sheared 

 and inverted Lower Torridonian rocks of Kyle Ehea, and it is 

 separated from these rocks by a band of siliceous mylonized rock and 

 by a considerable exposure of flaggy granulitic quartzite which con- 

 tains subordinate bands of garnetiferous biotite-schist. The mylonized 

 rock .lies next to the Torridonian Series, and the granulitic quartzite- 

 series comes between it and the series with which the limestones 

 are associated. There is little doubt that the mylonized rock occurs- 

 along the line of a great post-Cambrian thrust, which has been traced, 

 in a south-south-westerly direction, from Oronsay to near the Point 

 of Sleat, and, as we are informed by our colleague, Mr. B. N. Peachy 

 in a north-north-easterly direction for many miles on the northern 

 side of Loch Alsh. The granulitic quartzite which occurs on the east 

 side of the mylonized rock closely resembles the siliceous flagstones 

 east of the Moine thrust* of Sutherland and Northern Ross- shire.. 

 It is perhaps unsafe to conclude that the thrust near Glenelg is 

 a direct continuation of the Moine thrust of Sutherland ; but these 

 two thrusts have, at all events, played much the same part in 

 building-up the geological structure of the districts in which they 

 respectively occur. 



^ *0n the Occurrence of Sapphire in Scotland,' Min. Mag. vol. ix (1891) 

 p. 389. 



2 ♦ Summary of Progr. Geol. Surv. for 1897,' pp. 36-38. 



^ An eclogite from Totaig has already been described by Mr. Teall, Min.fMag. 

 rol. ix (1891) p. 217. Similar rocks occur abundantly in G-lenelg. 



■* See ' Eep. on Recent Work of Geol. Surv. in N.W. Highlands,' Quart.. 

 Journ. Geol. See. vol. xliv (1888) p. 412. 



