races of living things, and that same planet has marked them all. She has seen, too, as but a thing of yesterday, the appearance of man upon the scene, with all the successive centuries that have elapsed since then. Truly the "goddess of the silver bow" would have a strange story to tell us could we interrogate her about the past. But the days of Endymion have gone by, and she now no longer visits in a personal form the seat of beings who gaze at her crescent orb and daringly pronounce it a scene of blasted ruin and desolation. CHAPTER XI. Intercalation of coal seams among mountain limestone beds of Mid-Loihian--North Greens seam--Most of our coal seams indicate former land-surfaces--Origin of coal a debated question--Erect fossil trees in coal-measures--Deductions to be drawn therefrom--Difference between the mountain limestone of Scotland and that of England--Coal-bearing character of the northern series--Divisions of the Mid-Lothian coal-field--The Edge coals--Their origin illustrated by the growth of modern deltas--Delta of the Nile--Of the Mississippi--Of the Ganges--Progress of formation of the Edge coals--Scenery of the period like that of modern deltas--Calculations of the time required for the growth of a coal-field--Why of doubtful value--Roslyn Sandstone group--Affords proofs of a general and more rapid subsidence beneath the sea--Its great continuity--Probable origin--Flat coals--Similar in origin to the Edge coals below--Their series not now complete--Recapitulation of the general changes indicated by the Mid-Lothian coal-field. Among the old quarries of Roman Camp Hill and down the course of several streams in the same county, the limestone beds of the mountain limestone series are seen to be associated with strata of shale, some of which are highly calcareous, and charged with the same organic remains that occur in the limestones. Such shaly intercalations mark as before the transport and deposition of muddy sediment around and above the corals and stone-lilies of the sea-bottom. All these beds must undoubtedly be regarded as marine. But there occur, besides, seams of sandstone and black partially-bituminous shale, with layers of coal and fire-clay. To this singular intermixture it may be well to advert more particularly, since it forms one of the distinguishing features of these northern rocks, as contrasted with those of central and south-western England, and more especially since it will lead us to mark again the value of fossil remains as evidence of the ancient changes of land and sea.