DR BOUE' on the geognosy OF GERMANY. 93 
between Austria, Styria, and Hungary, and the primiti\'e 
country of the centre of France). It is yet possible that 
there may exist some varieties of primitive clay-slate as 
subordinate beds ; but in the whole of Germany, the Clay- 
slate, taken for primitive, I pronounce to be Transition, and 
to pass insensibly into Greywacke, (the Hartz, the Fran- 
kenwald, the Erzgebirge, the Carpathians, the Mountains 
on both sides of the Rhine from Bingen to Bonn, &c.) 
^. Transition Rocks. 
The Clay-slate Formation is improperly so called ; for 
this rock, as in Scotland and England, forms only a very 
small part, or, in other terms, only subordinate masses, in 
the extensive deposits of a great variety of rocks, produced 
by the various mixture of quartz, talc or mica, or chlorite, 
felspar, and a little calc-spar, or limestone. Such rocks are 
found, for instance, in the Alps of Savoy, on the banks of 
the Rhine, in the Erzgebirge, the Carpathians, and in the 
middle part of Bohemia, where these rocks are extremely 
interesting, by being composed of distinctly aggregated 
materials, and by their containing many subordinate beds 
or masses of various clay-slates impregnated with silica, or, 
in other words, of varieties of flinty slate and Lydian- 
stone. 
To these oldest transition-rocks, succeeds the Greywacke 
Formation, as, for example, in the Hartz, the Frankenwald, 
the chain of hills between Silesia, Bohemia, and Moravia. 
In these two transition-formations, the limestone forms here 
and there a series of separate deposits, placed on a line 
parallel to the general direction of the schistose beds ; and 
when these series are numerous, they seem to be, as in the 
primitive class of rocks, pretty parallel to each other. Some- 
times the limestone concretions are very extensive, 
