476 



THE GEOLOGIST. 



at all. In acquainting myself with the organic remains of this rock, 

 I found it most advantageous to work at the stone-heaps hy the road- 

 sides where it has been broken into small pieces, rather than at the 

 quarry where some of it is not very frangible, and where it is all ill- 

 exposed. This will both save labour and prevent disappointment. 

 Yery few genera of animals are represented in it, and scarcely any 

 genus by more than a single species ; but the individuals are numerous, 

 and so singularly persistent and distinctive in their forms that no 

 better defined species could be desired. A small sea-urchin is very 

 abundant and characteristic, but hitherto I only know it as an interior 

 mould and cannot safely determine its genus. It is either an Acrosalenia 

 or Pseudo-diadema ; but though I have collected as many as twenty 

 or thirty specimens in a morning I am in almost total ignorance about 

 the test. Once, too, and only once, I met with a trace of another and 

 larger urchin in the shape of a bit of an impression of (?) a Pedina or 

 Heinipedina. 



Thus there is a fair field at Hotham for any person interested in the 

 Echinoidea ; and this last specimen may probably prove to be a new 

 species. Eut some patience will be required for a successful hunt after 

 these tantalizing little animals, whose shells, according to my experi- 

 ence, are very difficult to be met with. 



Pinna, Modiola, and Pecten are the principal genera of shells ; and 

 each has a single prevalent species. I shall not pretend to have ascer- 

 tained these species. I neither know them myself nor can as yet 

 obtain any reliable information respecting them. The whole zone is 

 strange to me ; and while I am desirous to describe it as fully as I can, 

 there is much in it that I must leave for the present undecided. Any 

 palaeontologist, being at Hotham, would have no trouble in collecting 

 these shells ; and I should be glad to show such as still remain in my 

 possession to any geologist visiting Cheltenham. 



In the miscellaneous drift-bed to the north of Hotham, which I 

 discussed when speaking of Middle Lias, there occurs a rock so exactly 

 resembling the " Ligniferous Marl" in appearance, that I had, till 

 lately, no doubt of their identity, though I missed from it my fern- 

 leaves, urchins, and moUusks. And when I found in it that typical-shell 

 of the Upper Lias, Ammonites communis, and a faint impression of 

 another Ammonite which seemed to be ^. Lytliensis, I came fully to 

 the conclusion, for the time, that my Ligniferous Marl" was an 



