The remains of land Tortoises have been more rarely observed in a fossil state. Cuvier mentions but two examples, and these in very recent formations at Aix, and in the Isle of France.
Scotland has recently afforded evidence of the existence of more than one species of these terrestrial reptiles, during the period of the New red, or Variegated sandstone formation. (See Pl. 1, Sec. 17).. The nature of this evidence is almost unique in the history of organic remains.[1]
It is not uncommon to find on the surface of sandstone, tracks which mark the passage of small Crustacea and other marine animals, whilst this stone was in a state of loose sand at the bottom of the sea. Laminated sandstones are also often disposed in minute undulations, resembling those formed by the ripple of agitated water upon sand.[2]
- ↑ See Dr. Duncan's account of tracks and footmarks of animals, impressed on sandstone in the quarry of Corn Cockle Muir, Dumfriesshire Trans. Royal Society of Edinburgh, 1828.
Dr. Duncan states that the strata which bear these impressions lie on each other like volumes on the shelf of a library, when all inclining to one side: that the quarry has been worked to the depth of forty-five feet from the top of the rock; throughout the whole of this depth similar impressions have been found, not on a single stratum only, but on many successive strata; i. e. after removing a large slab which contained foot-prints, they found perhaps the very next stratum at the distance of a few feet, or it might be less than an inch, exhibiting a similar phenomenon. Hence it follows that the process by which the impressions were made on the sand, and subsequently buried, was repeated at successive intervals,
I learn, by a letter from Dr. Duncan, dated October, 1834, that similar impressions, attended by nearly the same circumstances, have recently been discovered about ten miles south of Corn Cockle Muir, in the Red sandstone quarries of Craigs, two miles east of the town of Dumfries. The inclination of the strata of this place is about 45° S.W. like that of almost all the sandstone strata of the neighbourhood. One of these tracks extended from twenty to thirty feet in length: in this place also, as at Corn Cockle Muir, no bones of any kind have yet been discovered.
Sir William Jardine has informed Dr. Duncan that tracks of animals have been found also in other quarries near Corn Cockle Muir.
- ↑ In 1831, Mr. G. P. Scrope, after visiting the quarries of Dumfries,
