Geological Society, 475 



coal measures. At first sight they presented a strong resemblance to 

 the marks which the hoof of a horse would leave on a soft surface, but 

 on a closer examination Mr. Babbage found that the part which should 

 have received an indentation from the frog was in relief, and resem- 

 bled rather a cast of the frog itself. The first mark examined by him 

 proved to be the letter G, which had been carved on the rock by some 

 person whose initials were G. H. This discovery made him inspect 

 the others more minutely, and he ascertained satisfactorily that they 

 were not artificial. Similar impressions were noticed by him at several 

 places on the moor. 



The author then referred to analogous casts in the old red sandstone 

 of Forfarshire, and there called Kelpies' feet. 



In attempting to account for the marks, Mr. Babbage described 

 some observations recently made by Mr. Lyell on impressions left by 

 Medusae on the rippled sand near Dundee. On removing the gela- 

 tinous body of the animal, a circular space was exposed, not rippled, 

 but having around half the border a depression of a horse-shoe form. 

 These marks, however, were not considered by Mr. Lyell as identical 

 with those called Kelpies' feet, but merely so far analogous as to in- 

 vite further observations, and to make it desirable to possess drawings 

 of the impressions which different species of Medusae leave, when 

 thrown by the tide upon a beach of soft mud or sand. 



A memoir *' On the occurrence of silicified trunks of large trees in 

 the new red sandstone formation or Poikilitic series, at Allesley, near 

 Coventry," by the Rev. Wm. Buckland, D.D,, Professor of Geology 

 and Mineralogy in the University of Oxford, was then read. 



In the great bed of gravel which overspreads the portion of War- 

 wickshire referred to in this paper, specimens of silicified wood had 

 been long found, and from being slightly rolled, it was conjectured 

 that they could not have been drifted from a distance, though no in- 

 dication of their original matrix had been observed. In the spring 

 of last year, however. Dr. Buckland was informed by the Rev. VV. T. 

 Bree of Allesley, that part of the silicified trunk of a tree, several feet 

 in length and a foot and a half in diameter, had been discovered in the 

 garden of the Rev. Mr. Gibson, at the bottom of Allesley Hill. On 

 visiting the spot in October last, the author ascertained that the 

 tree was not imbedded in the gravel, but in that portion of the new 

 red sandstone series, which consists of indurated sandstone, alterna- 

 ting with beds of conglomerate, chiefly made iip of sand and of peb- 

 bles of quartzite and compact forms of trap. 



In the churchyard of Allesley Dr. Buckland found an angular frag- 

 ment of similar silicified wood which had been fresh cast up from the 

 bottom of a grave, sunk to an unusual depth in the red sandstone ; 

 and in making a road from Allesley towards Coventry another large 

 tree was discovered a short time ago, and the greater part of it used 

 in forming the foundation of the road. On comparing the fragments 

 found in the gravel with the tree in Mr. Gibson's garden, which is 

 carefully preserved in its matrix, Dr. Buckland found so perfect an 

 identity in mineral character as to leave no doubt that the fragments 

 in the surface gravel had been derived from denuded beds of the new 

 red sandstone. 



3 P2 



