MALCOLMSON OLD BED SANDSTONE, 341 



the rich alluvial soil ivithin the ancient coast-line, that derived from 

 this sandstone being, for the most part, very sterile. This portion 

 of the system has suffered considerable disturbance, on the exami- 

 nation of which I cannot at present enter ; it is, however, necessary 

 to observe, that at several places within the limits assigned to these 

 sandstones, and interposed between their strata, a limestone resem- 

 bling the cornstones of Elgin and Cothall occurs, which is exten- 

 sively worked at Invemgie. On the coast near Lossiemouth it is 

 in great part composed of silica, much of which is finely crystallized. 

 At both these places a great deal of galena (with which Mr. Gordon 

 found specimens of blende) is disseminated through the rock, and is 

 most probably of contemporaneous formation, although in one or two 

 instances the ore is most abundant along the lines of fracture*. A 

 shaft has recently been driven through the Inverugie limestone 

 (which is 12 feet in thickness) into the white siliceous sandstone 

 below, but no ore was found in the inferior rock. 



Section through the Sandstones of the Flndliorn, showing the central 

 division resting directly on the Gneiss. (PI. XI. fig. 3.) — I shall 

 now proceed to describe the central or Cornstone series t? as it is dis- 

 played in the fine sections laid open by the River Findhom, which, 

 after a course of many miles through the wildest and most beautiful 

 scenery, emerges from a deep chasm in the gneiss (the perpendicular 

 sides of which exhibit innumerable ramifications of fine red granite- 

 veins) into more open reaches confined by mural cliffs of sandstone. 

 The discovery of numerous fossils in many of the strata interposed 

 between the gneiss and the Cothall limestone, described by Professor 

 Sedgwick and Mr. Mui^chison, will render it necessary to give some 

 details in addition to the brief notice contained in the admirable 

 memoir so often referred to J. The junction of the gneiss and sand- 

 stone on the left bank of the river, opposite Sluy (fig. 3), exhibits 

 the gneiss-strata bent into an arched form and traversed by granite- 

 veins, one of which crosses a vertical joint in the stratified rock, on 

 the opposite sides of which the gneiss dips at different angles, and 

 the vein itself is shghtly displaced. There are three of these fissures, 

 the second of which is a foot- and- a-half wide, fiUed with carbonate 

 of lime, mostly in the state of calc-spar, and mixed with green-earth, 

 and many of the specimens have the appearance of the finer parts of 

 the cornstones. This vein seems to have been filled from below ; 

 the gneiss near it is fractured by the granite, in several j^laces brec- 

 ciated, and altered into a ferruginous imperfectly laminated rock, not 

 very easily distinguished from some varieties of trap ; minute rami- 

 fications of calc-spar also are diffused through its most solid parts. 



* See Weaver on the geological relations of the South of Ireland (Geol. 

 Trans, vol. v. p. 60). The relations of these rocks cannot, however, be con- 

 sidered as having been sn.fficiently determined. 



t From the occurrence of cornstone in other parts of the system, I would 

 venture to suggest that it sliould not be used as a general term to distinguish one 

 part of the system from another. 



j Geol. Trans. 2 ser. vol. iii. p. 150. 



