DEPOSITS OF ASSYNT.

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in their interior. In the better, at least more distinct, spe-cimens, they somewhat resemble fragments of serpula, or thosesegments of dentalia which one occasionally finds in theboulder-clay of Caithness ; but they are in all probabilitynot the remains of either annelid or mollusc, but mere effectsof the oxydization, under peculiar circumstances, that has dis-coloured the matrix, in which they lie. Iron pins or nailswe find not unfrequently represented on sea-beaches wherewrecks have taken place, or near some dockyard or harbour,by mere oxydized tubes, hollow within; and it is not im-probable that to minute pin-like crystals of some mineral ormetal now represented by only the oxydized substance en-closed within the hollow, do these little tubes owe their origin.

I at least wholly failed to satisfy myself that they are organicin their character ; nor do I suppose that they would be byany means the oldest of Scottish fossils, even if they were.

This upper quartz rock forms the highest and most moderndeposit of the marble districts. Taking the summit of Ben-more as its apex, a shaft sunk on the top of that noble hill,to the depth of perhaps eight or ten thousand feet, would passin succession through the first or upper quartz, through thelimestone with its associated marbles and flagstones, throughthe second or lower quartz, through the red sandstone, withits conglomerate beds; and finally, it would reach the uncon-formable gneiss, on which the whole system rests; for asone system must these four great deposits be regarded. Where,among the other systems of Scotland , I ask, are we to seekfor its analogue and representative 1

Let me first remark, that the Lower Old Red Sandstoneof the east coast of Scotland , as developed in Inverness , Ross,Cromarty, Sutherland, Caithness, and the Orkney Islands ,consists of exactly the same number of great divisions as thissystem of the western coast. That subordinate Red Sand-stone of the western system which has been coloured a a Old