CHAPTER IX. Fossils of the Upper Old Red Sandstone much more imperfectly preserved than those of the Lower.--The Causes obvious.--Difference between the two Groups, which first strikes the Observer, a difference in size.--The _Holoptychius_ a characteristic Ichthyolite of the Formation.--Description of its huge Scales.--Of its Occipital Bones, Fins, Teeth, and general Appearance.--Contemporaries of the _Holoptychius_.--Sponge-like Bodies.--Plates resembling those of the Sturgeon.--Teeth of various forms, but all evidently the teeth of fishes.--Limestone Band and its probable Origin.--Fossils of the Yellow Sandstone.--the _Pterichthys_ of Dura Den.--Member of a Family peculiarly characteristic of the System.--No intervening Formation between the Old Red Sandstone and the Coal Measures.--The _Holoptychius_ contemporary for a time with the _Megalichthys_,--The Columns of Tubal-Cain, 151-172 CHAPTER X. Speculations in the Old Red Sandstone, and their Character.--George, first Earl of Cromarty.--His Sagacity as a Naturalist at fault in one instance.--Sets himself to dig for Coal in the Lower Old Red Sandstone.--Discovers a fine Artesian Well.--Value of Geological Knowledge in an economic view.--Scarce a Secondary Formation in the Kingdom in which Coal has not been sought for.--Mineral Springs of the Old Red Sandstone.--Strathpeffer.--Its Peculiarities whence derived.--Chalybeate Springs of Easter Ross and the Black Isle.--Petrifying Springs.--Building-Stone and Lime of the Old Red Sandstone.--Its various Soils, 173-189 CHAPTER XI. Geological Physiognomy.--Scenery of the Primary Formations; Gneiss, Mica Schist, Quartz Rock.--Of the Secondary; the Chalk Formations, the Oolite, the New Red Sandstone, the Coal Measures.--Scenery in the Neighborhood of Edinburgh.--Aspect of the Trap Rocks.--The Disturbing and Denuding Agencies.--Distinctive Features of the Old Red Sandstone.--Of the Great Conglomerate.--Of the Ichthyolite Beds.--The Burn of Eathie.--The Upper Old Red Sandstones.--Scene in Moray, 190-210 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, 211-225 CHAPTER XIII.