STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 7 



gigantic reeds are in the cliffs near High Whitby. They appear to 

 have been rooted in a bed of shale or slate-clay and their remains 

 protrude into a sandstone, 5 feet thick. Those which are erect 

 retain their shape, but prostrate stems are compressed. The tops 

 seem to have been broken off and the woody matter has disappeared, 

 there being only sandstone casts. Phillips gave more of detail. He 

 reports that a Lias sandstone near Whitby contains great numbers 

 of cylindrical plants like Equiseta, which are erect. They were 

 broken off above and in some cases do not reach to the top of the 

 bed. They are broken off below but commonly pass to the lower 

 surface of the bed and, at times, the lower joints reach into the 

 underlying shale. The conditions have led some to regard these 

 plants as in situ, but Phillips prefers to believe that they were 

 floated down and that they were kept vertical by the weight of 

 their roots. The writer is compelled to dissent from this explana- 

 tion. If the trees had been floated down stream, they would not 

 remain vertical, even though it be conceded that the weight of their 

 roots would keep them vertical while floating. As soon as the roots 

 had touched bottom, the current, gentle or strong, would push the 

 stem down stream. " Snags," only too familiar in our western 

 rivers, invariably point down stream. Grand' Eury was able to 

 determine the direction of currents in St. Etienne coal basin by 

 means of " snags " enclosed in the sandstones. Murchison,^^ in a 

 brief note referring to the observations by Phillips, stated that he 

 had discovered another locality at the same horizon, but 40 miles 

 away and well inland. At both localities, the stems of Equisetum 

 columnare are in the normal position and appear to be rooted in the 

 black shale. The only fossil accompanying these plants is a fresh- 

 water bivalve. 



France. — The Jurassic deposits of France contain some thin 

 seams of coal, which rarely have more than local importance, de 

 Serres^'^ reported upon the coals of Aveyron, belonging to the Lower 

 Oolite. The mines are on the plateau of Larzac within an area of 



^s R. I. Murchison, " On the Occurrence of Stems of Fossil Plants in 

 Vertical Position, etc.," Proc. Geol. Soc, Vol. i, 1834, p. 391. 



IS M. de Serres, " Des houilles seches ou stipites des terrains jurassiques, 

 etc.," Bull. Soc. Geol. France, t. 16, 1859, pp. 97-99, 104, 105. 



