252 CATALOGUE OF THE LOCAL FOSSILS IN THE 



at Ferryhill Station. It cannot be used for building purposes, and 

 no fossil could be preserved or expected to be preserved in it. 

 It has been deposited on the disturbed and denuded edges of the 

 Coal-measures, and may have been an Eolian accumulation of 

 sand on the shores of the old Carboniferous Sea before the Mag- 

 nesian-limestone began to be thrown down. It may be the 

 English equivalent of the German Weissliegende, which is also 

 an anomalous deposit, and, if so, must be admitted to be Per- 

 mian, as the Weissliegende, in some parts of Germany, contains 

 characteristic and well-known Magnesian-limestone or Permian 

 species. There is no Rothliegende in these counties, the beds 

 so classified are merely the disturbed denuded edges of the true 

 Coal-measures. 



CARBONIFEROUS. 



The Carboniferous rocks of Durham and Northumberland may 

 be grouped under the following heads, viz. : — 



Coal Measures. — Beds of sandstone, grits, and shales, with Stigrnarian- 

 clays and thick beds of coal. Bands of clay ironstone and shell-hands 

 filled with Anihracosia. 



Gannister series. — Thin bedded sandstones or flagstones and shales, with 

 thin seams of coal and hard, crystalline, siliceous beds (gannister) full of 

 rootlets of Stigmaria. 



