Geological Society. 49/ 



of the water, and the quarter towards which the animals were 

 pausing ; the latter is indicated by the direction of the footsteps which 

 form their tracks ; the size and curvatures of the ripple-marks on 

 the sand, now converted to sandstone, show the depth and direction 

 of the current ; the oblique impressions of the rain drops register 

 the point from which the wind was blowing, at or about the time 

 when the animals were passing. 



Demonstrations founded solely upon this kind of circumstantial 

 evidence were duly appreciated, and are well exemplified, by the 

 acute author of the story of Zadig ; who from marks he had noticed 

 on the sand, of its long ears, and teats, and tail, and from irregular im- 

 pressions of the feet, declared the size and sex, recent parturition and 

 lameness of a bitch he had never seen ; and who from the sweeping of 

 the sand, and marks of horse-shoe nails, and a streak of silver on a 

 pebble that lay at the bottom of a single footstep, and of gold upon 

 a rock against which the animal had struck its bridle, inferred that 

 a horse, of whose existence he had no other evidence, had recently 

 passed along the shore, having a long switch tail, and shod with 

 silver, with one nail wanting upon one shoe, and having a bridle 

 studded with gold of twenty carats value. 



March 25. — A paper was first read " On the Age of the Lime- 

 stones of South Devon ;" by W. Lonsdale, F.G.S. 



The object of this communication is to show the nature and limits 

 of the author's claim to having been the first to infer from zoological 

 evidence that the limestones of South Devon would prove to be of the 

 age of the old red sandstone; and it was drawn up at the request of 

 Mr. Murchison, in consequence of the subsequent adoption and ex- 

 tension of the proposed classification by Professor Sedgwick and 

 that gentleman ; and at the request likewise of Dr. Fitton, in conse- 

 quence of the same views having been applied to some of the in- 

 fra-carboniferous formations of Belgium and the Boulonnais. The 

 paper commences with a summary of the opinions previously enter- 

 tained respecting the age of the limestones. The authors quoted are, 

 Woodward, 1722 ; Da Costa, Maton, Play fair, Berger, L. A. Necker, 

 De Luc. T. Thomson, Kidd, W. Smith, Brande, W. Phillips, Hennah, 

 Greenough, Sedgwick, W. Conybeare, J. J. Conybeare, Buckland, 

 Dufrenoy, Elie de Beaumont, De la Beche, Prideaux, Boase, J. 

 Phillips, Austen, Murchison, Bakewell and J. de Carle Sowerby. 



By these geologists the limestones are placed in the primary, trans- 

 ition or gray wacke and carboniferous series ; Mr. Prideaux being 

 the only author who ascribes them in part, and on mineral characters, 

 to the old red sandstone ; and Mr. J. Phillips, in his article on geo- 

 logy in the Encyclopaedia Metropolitana, hesitating to place them 

 in a definite position, in consequence of the resemblance of many of 

 the shells to species found in the mountain limestone. Mr. De la 

 Beche, in his memoir on Tor and Babacomb Bays, also states that 

 the limestones of that district rest on old red sandstone ; and in his 

 Report on Cornwall and Devonshire (1839), he says, "that those 

 who rely very exclusively on the character of organic remains would 



Ann. §■ Mag. N. Hist. Vol. vi. Suppl. 2 k 



