420 PSOCEEDINGS OF THE GEOLOGICAL SOCIETY. [DcC. 15, 



In the long narrow promontory of Tarbet Ness, to the E. of Tain, 

 described in 1827 by Sedgwick and myself, the lower old red sand- 

 stone, resting upon the gneissose, granitic, and felspathic rocks of the 

 Sutors of Cromarty, is followed on the north by a zone with ichthy- 

 olites, representing in miniature the great expanded masses of the 

 Caithness Flags ; and it is this zone which afforded to the scrutiny of 

 Hugh Miller not only many Caithness forms, but also the Coccosteus 

 and other types of the deposit which he was the first to describe. 

 In this promontory, also, which juts out immediately opposite to the 

 coast of Moray on the opposite side of the Firth of that name, the 

 sandstones into which the central member of the Old Eed passes 

 upwards are of light yellowish colours, and on these stands the 

 Tarbet Ness Lighthouse *. They are, in fact, an eastern portion of 

 the yellow sandstones of Dornoch Firth and Tain (see p. 398). 



In the other and interior parts of Ross-shire the central or ichthy- 

 olitic zone becomes still more attenuated, being visible in one district 

 only, or Strathpeffer ; but, although not detected in the banks of the 

 Connan or the Orron, or in the Black Isle, where the sandstones and 

 conglomerates are covered by much drift and laid bare at intervals 

 only, it is probable that a feeble representative of the Caithness Flags 

 may some day be discovered, inasmuch as in the eastern extremity 

 of Inverness- shire, and not far to the S.E. of the town of Inverness, 

 these bituminous schists recur in small dimensions at Inches, as 

 pointed out to Sedgwick and myself by Mr. George Anderson. 

 Thence the zone is traceable at intervals eastwards through Nairn- 

 shire into Moray ; and at Lethen Bar and Clune it contains argiUo- 

 calcareous nodules, which afforded to the researches of Dr. Malcolm- 

 son and Lady Cumming Gordon the well-known fossil fishes described 

 by Agassiz. 



Now, although these fishes are essentially the same as those of 

 Caithness, we already see how the great central deposit of flagstone 

 has dwindled away to a mere stratum. 



From this point the Old Red group, trending from W.S.W. to 

 E.N.E., and dipping away to the N.N.W. usually at low angles, re- 

 poses on the flaggy micaceous gneissose rocks with granitic intrusions. 



As the group is much denuded, as well as obscured by drift in its 

 course through Nairnshire and Morayshire, it is not surprising that 

 the slender nodular fish- zone or representative of the Caithness flags 

 should be so rarely detected. The Lower Sandstone or Conglomerate 

 is also of much less dimensions than in the northern counties of 

 Caithness, Sutherland, and Ross. The River Findhorn in its course 

 from south to north, on to Forres and the Moray Firth, exposes on 

 its banks the best succession. 



But, before I proceed to consider the adjacent tract around Elgin 

 into which the strata seen upon the Findhorn are extended, it is 

 essential that I should do justice to the other observers who, be- 

 tween the period when Professor Sedgwick and myself first rambled 

 over this country and the present day, have thrown light upon its 

 structure. 



* See Trans. Geol. Soc. Lond. 2nd ser. vol. iii. p. 150, pi. 14. fig. 4. 



