198 . LAND TORTOISES- 



The remains of land Tortoises have been more rarely ob- 

 served in a fossil state. Cuvier mentions bat tvv^o example s, 

 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 forma- 

 tion. (See PI. 1, Sec. 17.) The nature of this evidence is 

 almost unique in the history of organic remains.* 



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.f 



* See Dr. Duncan's account of tracks and footmarks of animals im- 

 pressed on sandstone in th3 quarry of Corn Cockle Muir, Dumfries-shire 

 Trans. Royal Society of Edinburgh, 1828. 



Dr. Duncan .states tliat 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-fivo feet from the top 

 of the rock; llirougliout the whole of this dcptli similar impressions have been 

 found, not on a single stratum only, but on many successive strata; i. c. af- 

 ter removing a large slab Vvhich 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 plienomenon^ Hence it follows that tlie pro- 

 cess 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, tliat similar 

 impressions, attended by nearly the same circumstances, have recently been 

 discovered aboutten 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 ihis place is about 45° S. W. like that of almost all tlie sand- 

 stone 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. 



t In 1831, Mr. G. P. Scrope, after visiting the quarries of Dumfries. 



