376 



THE GEOLOGIST, 



BO that it lias obtained the name of Jandscapc-stonc, near Bristol, 

 -svhere it is frequently quarried, and used for ornamental 

 purposes. It contains a small bivalve, which may be a fresh- 

 water shell Cypris,^'' and three species of Monocotyledonous aquatic 

 plants belonging to the family Is aiades, some genera of which may still 

 be observed in ponds and ditches, though others inhabit the sea. This 

 limestone is readily recognized by its position, fossils and lithological 

 structure, and is distinct from the overlying band. It is well exhibited 

 at "Wainlode, AVestbury, and Aust Passage, where it is considerably 

 thicker, and contains some well-preserved insects and two new species 

 of small fish. Twelve feet of yellow clay and black shale divide the 

 above from the celebrated " bone -bed," of which there are two layers at 

 "Wainlode Cliff, the upper one being a hard sandstone, the surface of 

 which is covered with various markings and tracks of mollusks and 

 marine worms, and the other, about ten feet lower, of a dark colour, 

 full of pyrites, and almost composed of bones, teeth, and scales of fish 

 and saurians; at Coombe Hill, AYestbury, and Aust it is much 

 thicker, and contains some singular palatal teeth of Ceratodus. Two 

 feet of black shale separate this from the green and red marls of the 

 Trias, or 'New Eed system. Prom the characters of the fossils which 

 mark these ''bone-beds," it has been inferred that they w^ould be more 

 correctly assigned to the Trias ; at all events, there is something 

 peculiar and distinctive about them ; and it is a striking fact that 

 though sometimes blended together, they can be traced even into Wales, 

 the main mass still being made up of bones, scales, teeth, and coprolites of 

 fish and saurians. The quantity of phosphatic matter, indeed, is in places 

 so considerable that it might be used profitably as a manure, if it were 

 not so strongly impregnated with pyrites. A good deal might be said 

 about the history of these '' bone-bec!s,"f which are known in other 

 formations as well as the Lias, when similar conditions seem to have 

 prevailed at distinct and widely distant intervals of time in the early 

 history of our globe. In concluding the account of the Lias in 

 Gloucestershire, we may, for one moment, carry our thoughts back to 

 the state of the land and water during its deposition. The sea must 

 have been highly charged with calcareous matter, usually making an 

 Frcsh-watcr crustjiooa iuliabiting a bivalve shell, 

 t A very probable \iew of the ori.j;iu of the^<c bone bcd^ '' is given in " Stones 

 of the Valley," page 18, an able aii'l interesting i^ovk lately published by my 

 fncud, the llcv. W. S. vSymouds, F.G.S., Rector of Pcndock.— P. 13, 13. 



