50 
room viii. of the three usual constituent parts, (a fragment of 
NatTh^t immense mass of granite conveyed from the 
bay of Finland to St. Fetersburgh, and now 
forming the base of the equestrian statue of Peter 
the Great) ; granite in several stages of decom- 
position ; new or regenerated granite from the 
Hartz, &c. ; binary aggregates, called Granitels 
by some authors, (graphic stone from Siberia, 
Sweden, &c.) ; granite mixed with other minerals, 
such as common shorl, garnets, actinote, chlorite ; 
large polished pieces of granitic rocks, some of 
them passing over into sienite and porphyry; — 
gneiss of various approximation to granite on one 
side, and to micaceous shistus on the other ; gneiss 
with garnets, shorl, &c— micaceous shistus ; the 
same approaching gneiss on one hand, and clay 
slate on the other, (silvery variety of the latter, 
used for roofing in Thuringia). 
case [Shelves 4, 5, 6.) Oldest or primitive clay slate 
of several colours ; variegated slate. Subordinate 
beds in clay slate: novaculite or whet slate, chlorite 
slate, drawing slate, better known by the name or 
black chalk ; flinty slate and Lydian stone ; an- 
thracolite or kohlenblende. — Transition slate, 
mostly from the Hartz mountains, (a specimen, 
in which it is seen in immediate contact with grey 
wacke, a transition rock of the nature of old 
sandstone) Grey-wacke, fine and coarse grain- 
ed 
