There ascends from the apex a thin, blue column of smoke--that of a lime-kiln. That ridge and promontory are composed of the thick limestone band, which, in Moray as in Fife, separates the pale red from the pale yellow beds of the Upper Old Red Sandstone; and the flattened tracts on both sides show how much better it has resisted the denuding agencies than either the yellow strata that rests over it, or the pale red strata which it overlies. CHAPTER XII. The two Aspects in which. Matter can be viewed; Space and Time.--Geological History of the Earlier Periods.--The Cambrian System,--Its Annelids.--The Silurian System.--Its Corals, Encrinites, Molluscs, and Trilobites.--Its Fish.--These of a high Order, and called into Existence apparently by Myriads.--Opening Scene in the History of the Old Red Sandstone a Scene of Tempest.--Represented by the Great Conglomerate.--Red a prevailing Color among the Ancient Rocks contained in this Deposit.--Amazing Abundance of Animal Life.--Exemplified by a Scene in the Herring Fishery.--Platform of Death.--Probable Cause of the Catastrophe which rendered it such. "There are only two different aspects," says Dr. Thomas Brown, "in which matter can be viewed. We may consider it simply as it exists, in space, or as it exists in time. As it exists in space we inquire into its composition, or, in other words, endeavor to discover what are the elementary bodies that coexist in the space which it occupies; as it exists in time, we inquire into its susceptibilities or its powers, or, in other words, endeavor to trace all the various changes which have already passed over it, or of which it may yet become the subject." Hitherto I have very much restricted myself to the consideration of the Old Red Sandstone as it exists in _space_--to the consideration of it as we now find it. I shall now attempt presenting it to the reader as it existed in _time_--during the succeeding periods of its formation, and when its existences lived and moved as the denizens of primeval oceans. It is one thing to describe the appearance of a forsaken and desert country, with its wide wastes of unprofitable sand, its broken citadels and temples, its solitary battle-plains, and its gloomy streets of caverned and lonely sepulchres; and quite another to record its history during its days of smiling fields, populous cities, busy trade, and monarchical splendor. We pass from the dead to the living--from the cemetery, with its high piles of mummies and its vast heaps of bones, to the ancient city, full of life and animation in all its streets and dwellings.