occupying the great mass of the island, from the difference of their external characters and form, and from the existence of some particular varieties in the one, which are not found in the other: but I have not the means of drawing this distinction, nor of saying where or how they are connected or disjoined. I have little doubt that there are distinct deposits of trap rock of different periods, as well as that there are veins of the same; but whether these two leading divisions in the external appearance of Sky are also distinctions in the geological æra of the rocks which form them, is more than I can determine, since they have no distinct set of connections by which such a supposition could be verified. Further, when I attempt to trace their connection with each other, I imagine that I can every where see the mountain trap of the Cuchullin, blending with the stratified trap of the coast; and this opinion is confirmed by every thing which I have observed in Mull, where every possible variety of this rock from Gribon to Ben More, and thence to Loch Don on one hand, and Mornish on the other, appear to succeed each other without discontinuity or interruption, and with changes of character so gradual, that no line of interruption can any where be found. As however I consider this to be an object of the first importance in the history of this rock, I shall still suspend my judgment, pointing it out to other geologists as a subject highly worthy of investigation.
As I consider the term flœtz to be in this case improper, since it implies the hypothesis from which it is borrowed, I have distinguished that trap which is placed in a horizontal form, and of which the terraced edges are so very characteristic, by the name of stratified trap, using the term beds or strata indifferently, and without meaning by the use of either to insinuate any thing respecting
