Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/204

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Although these footsteps are thus abundant in the extensive quarries of Corn Cockle Muir, no trace whatever has been found of any portion of the bones of the animals whose feet they represent. This circumstance may perhaps be explained by the nature of the siliceous sandstone having been unfavourable to the preservation of organic remains. The conditions, which would admit of the entire obliteration of bones, would in no way interfere with the preservation of impressions made by feet, and speedily filled up by a succeeding deposite of sand, which would assume, with the fidelity of an artificial plaster mould, the precise form of the surface to which it was applied.

Notwithstanding this absence of bones from the rocks which are thus abundantly impressed with footsteps, the latter alone suffice to assure us both of the existence and character of the animals by which they were made. Their form is much too short for the feet of Crocodiles, or any other known Saurians; and it is to the Testudinata, or Tortoises, that we look, with most probability of finding the species to which their origin is due.

markings occur in the Old Red Sandstone, which are referred by the natives to the tracks of Horses, and the impressions of Patten-rings, and legendary tale has been applied to explain their history. They are caused by concretions of Marlstone and Iron, disposed in spherical cases around a solid core of sandstone, and intersected by these water courses.