26& Proceedings of the 



especially in the fresh-water or estuary group of that system known as 

 the Burdiehouse limestones. This tooth, imbedded in its matrix of fine 

 laminated clay, was given to the late Professor Edward Forbes, who at- 

 tached much importance to the discovery. He expressed a desire to have 

 it thoroughly identified by the best authority on fossil fishes, and it was 

 to have been sent to England by him for that purpose a short time before 

 his death. I am not aware whether it was sent, or what has now become 

 of it. It was in the hope that this specimen might have been found 

 amongst those left by Professor Edward Forbes to the Museum of the 

 University of Edinburgh, that I delayed making public notice of this 

 discovery to the Royal Physical Society. The assistant-conservator of 

 the University Muse am (Mr Davies) has carefully searched the collection 

 of Professor Edward Forbes without being able to find our specimen. 

 It is therefore unlikely that this fossil tooth will now be forthcoming. 

 The other fossil organism evidently belongs to the vegetable kingdom. 

 Several specimens have been found, but they all appear to be mere frag- 

 ments. The few specimens which I have kept are very poor representa- 

 tives. Short spines can readily be observed on some of the fragments ; 

 but I find a difficulty in deciding whether they have originally been ver- 

 ticillate, opposite, or alternate on the stem. The distinctness of their 

 general outline may furnish, however, a tolerably safe guide for com- 

 paring them with a complete series of other fossil plants by which their 

 geological position may be inferred. The nearest resemblance to these 

 specimens which I have seen figured in plates is that of Bechera charce- 

 formis, accompanying the Memoir of Mr Joseph Prestwick, " On the 

 Geology of the Coalfield of Coalbrookdale," from the Transactions of the 

 Geological Society of London, vol. v. for 1840. The lithological character 

 of the shale bed in which these organisms occur is chiefly composed of thin 

 layers of fine clay and earthy greenstone, containing variable proportions 

 of siliceous and calcareous materials. The vegetable impressions are seen 

 in great abundance, lying parallel to the plane of the sedimentary depo- 

 sition of the several layers, six of which can at least be observed, from 

 one to six or eight inches in thickness, indicating a quiescent and inter- 

 mittent condition of the carrying power which brought and assorted these 

 materials into their present position. Other parts of Arthur's Seat, hav- 

 ing reference to fossil remains, have been carefully examined, but, so far 

 as I know, as yet without success. At the Windy Gowl, on the south side 

 of the hill, on the road to Duddingston, under what Mr Maclaren, in his 

 excellent work, " The Geology of Fife and the Lothians," calls the Girnal 

 Crag, there is a bed of hard cherty limestone, covered by the bed of sand- 

 stone on which the porphyritic greenstone bed of the crag rests. This lime- 

 stone bed I have repeatedly examined, but without finding a trace of fossil 

 remains. The Girnal Cragis considered by Mr Maclaren and other competent 

 geologists to be the equivalent of Bog Crag, the first on the east rising 

 from the hollow termed the Hunter's Bog, on the north side of the hill. 

 Under a portion of Bog Crag, presenting an example of what is called a 



