19 
sandstone). — Grey-wacke, fine and coarse room viii. 
grained and approaching to conglomerate, from Nat . hist, 
the Hartz, where the metallic ores are principally 
found in it,—Fletz (secondary) rocks of this 
formation ; sandstone; oldest sandstone with 
and without petrifactions ; old red and white 
sandstone (Todliegendes of the German mi¬ 
ners) ; variegated sandstone, filtering stone ; 
sandstones of large grained concretions passing 
over into conglomerates, to which, in point 
of external appearance, may also be referred 
some kinds of breccia and puddingstone (the 
beautiful Breccia verde d'Egitto composed princi¬ 
pally of rounded pieces of green pebbles ap¬ 
proaching the nature of hornstone, of granite, 
&c. in a mass which is itself a fine grained pud¬ 
dingstone).* As subordinate to the old sand¬ 
stone formation are added some kinds of coal, 
together with specimens of slate clay (Fletz clay 
slate of some), generally forming the immediate 
roof of beds of coals ; slate clay with the charac¬ 
teristic impressions of vegetables, from Ilmenau 
in Thuringia, where it alternates with coal and 
sandstone; from Planitz, &c.; common clay iron 
I 
stone. 
* The largest and most valuable monument now known to 
exist of this breccia is the Alexandrian Sarcophagus in the Gallery 
©f Antiquities of the Museum. 
