THE LAKE OF STENNIS. 3 



low promontory whicli forms the western boundary of the 

 harbour. The granite here is a ternary of the usual com- 

 ponents, somewhat intermediate in grain and colour between 

 the granites of Peterhead and Aberdeen ; and the Conglo- 

 merate consists of materials almost exclusively derived from 

 it, — evidence enough of itself, that when this ancient me- 

 chanical deposit was in course of forming, the granite — ex- 

 actly such a compound then as it is now — was one of the 

 surface rocks of the locality, and much exposed to disinte- 

 grating influences. This Conglomerate base of the Old Red 

 Sandstone of Scotland, which presents, over an area of many 

 thousand square miles, such an identity of character, that 

 specimens taken from the neighbourhood of Lerwick, in Shet- 

 land, or of Gamrie, in Banff, can scarce be distinguished from 

 specimens detached from the hills which rise over the Great 

 Caledonian Yalley, or from the cliffs immediately in front of 

 the village of Contin, seems to have been formed in a vast 

 oceanic basin of primary rock, — a Palaeozoic Hudson's or 

 Baffin's Bay, — partially surrounded, mayhap, by primary con- 

 tinents, swept by numerous streams, rapid and headlong, and 

 charged with the broken debris of the inhospitable regions 

 which they drained. The graptolite-bearing grauwacke of 

 Banffshire seems to have been the only fossiliferous rock that 

 occurred throughout the entire extent of this ancient northern 

 basin ; and its few organisms now serve to open the sole vista 

 through which the geological explorer to the north of the 

 Grampians can catch a glimpse of an earlier period of exist- 

 ence than that represented by the ichthyolites o^ the Lower 

 Old Bed Sandstone.* 



Yery many ages must have passed ere, amid waves and 

 currents, the water-worn debris which now forms the Great 



* [Since the discovery of Maclurea and other Silurian foims in the 

 North- West Highlands, by Mr C. Peach, this is no longer the case. — 

 See Appendix, A.] 



