124 Mr Lyell on a Dike of Serpentine cutting- through 



fication becomes obscure in proportion to its proximity to the 

 greenstone. 



Although no serpentine is seen here, I am informed by Mr 

 Blackadder of Glammis, that, in following the course of the 

 dike" through the neighbouring fields, he found blocks of ser- 

 pentine on the land, from which it appears that that rock is 

 either connected with 3 or replaces the greenstone. 



About three miles farther to the south-west of the last 

 mentioned locality on the Isla, serpentine, like that on the Ca- 

 rity, occurs to the south of Bamff, near Alyth, in Perthshire, 

 the seat of Sir James Ramsay, Bart. The greenstone and 

 serpentine of Clunie, in Perthshire, described by Dr MacCul- 

 loch, is only nine miles distant from the last mentioned place, 

 and precisely in the same line. 



This is certainly a remarkable fact, although not sufficient 

 to lead us to conclude, that the Clunie dike is a prolongation 

 of that which we have been tracing through the country ; for 

 no serpentine can be found on the banks of the Erroch, a ri- 

 ver which intervenes between Clunie and BamfF, and which, 

 like all the other rivers descending from the Grampians into 

 Strathmore, affords a deep section of the strata. * There are 



" The section of the rocks on the Erroch, ascending from Blairgowrie 

 to the northward of Craig-Hall, differs, in one respect, from any of those, 

 which I have seen hetween that river and the sea of Stonehaven, or from 

 any that I have examined in the Seedlay Hills, or in the cliffs between 

 Auchmithie and the Red Head. This difference consists in the absence of 

 the inferior fine-grained sandstone, shale, &c. The conglomerate, com- 

 posed chiefly of rounded masses of trap-porphyries, continues above Craig- 

 Hall, forming precipitous cliffs, till we arrive nearly opposite East Drum- 

 mie. There trap rocks succeed, and nothing else appears until opposite 

 the Milltown of Drummie, where greywacke and clay-slate are seen. 



It may be suggested, that the trap, which succeeds the conglomerate, 

 is an overflowing mass, and conceals strata of inferior or transition sand- 

 stone. In answer to this, I should state, tbat we might rather expect 

 greywacke and clay-slate, were the trap not present. For it is only ne- 

 cessary to consider on the map, the general line of bearing of the inferior 

 or transition sandstone series through Kincardineshire and Forfarshire, 

 at the foot of the Grampians ; and it will appear highly improbable that it 

 exists so far to the north as East Drummie. May we not conclude that 

 the inferior sandstone strata, which have, in all instances, suffered under 

 the influence of that violent action which formed the great conglomerate, 

 have here been completely annihilated. We find almost universally in 



