﻿1861.] 



MUKCHISOX AND GEIKIE— HIGHLANDS. 



221 



group — a much more complete series than appears to occur any- 

 where else east of the line of the Caledonian Canal. 



Fig. 22. — Section of ScJiiehdllien, Perthshire. 



N.W. Scliiehallien. S.E. 



Quartz-rock with some schist and a bed of limestone. Schists and a bed 



of limestone. 



At the time when our observations were made, we believed that 

 in this second limestone we had found tbe prolongation of the great 

 lower calcareous zone which in Sutherland and Boss, as well as far 

 to the southward, in Islay, subdivides the quartzose group into an 

 upper and an under series. The extension of our survey to the 

 north and to the east served to confirm this inference. We found 

 the limestone as it stretched northward become thinner, until, not 

 far beyond Glen Erochie Inn (above which, on the north side of the 

 valley, it has been worked), it appears to die away altogether; and 

 it does not occur in the consecutive section along the channel of the 

 Eiver Garry. 



Here, then, along the great anticlinal axis of the Breadalbane 

 Forest already described, there is a lower part of the series brought 

 up than at any other locality throughout this tract. It is important 

 to remark, too, that the greater extent of the curve only serves to 

 bring up strata already known in other districts, and which could 

 have been confidently predicted to exist here, as soon as it had been 

 ascertained that there occurred a lower set of beds than the flag- 

 stones of the Black Mount. Thus confirmatory evidence is obtained 

 of the correctness of the present explication of the order of succession 

 throughout the Central Highlands. 



Dednaecerdoch to Blear*. — As the road winds over the hills from 

 Glen Erochie to Dalnaeardoch, a marked dyke of porpbyritic felstone 

 with hornblende strikes through the limestone and the micaceous 

 flagstones in a nearly north and south direction, and runs for a long 

 way northward. It occurs again in the bed of the Garry, at Dalna- 

 cardoch Inn, and on the hill above the road, with a breadth of 15 or 

 20 feet and a strike from S.S.W. to N.N.E. How much further 

 north it extends we did not ascertain. 



There is an admirable section of the quartzose series along the bed 



* This tract, according to Macculloch (Trans. Geol. Soc. 1st series, vol. iii. 

 p. 297), is wholly, or in great measure, composed of bard argillaceous schist, gra- 

 duating into argillaceous quartz-rock, and more rarely into mica-schist, with 

 granite-veins here and there dispersed through it. 



