110 FORESTRY OF NORWAY. 
argilaceous schists of this layer. Above, on its surface, 
the layer presents on many parts a hard conglomerate, 
erratic blocks of quartz in which appear to have come 
from ancient quartzose mountains in like manner destroyed, 
and among these blocks are also found fragments of the 
old:granite, pure and simple. 
No fossils have been found in this layer; but it is 
considered as the base of the taconic formation, and it lies 
in a position divergent from that of the horizontal strata 
on vertical layers of. the. fundamental rock. Fossils have 
been found at Hogberg, near the river Klara Elv, to the 
south of Kvitvolfjeld. 
Sandstone is met with on the surface of the sparagmitic 
land in the part to the east of Trysel, whence are obtained 
the famous white stones bearing that name. 
On the sparagmitic formations in the western part of 
the plateau of the Oplande rests the second layer of the 
taconie formation, composed of argilaceous micaceous 
schist and limestones, with rarely occurring débris of nas- 
cent animal organisms. From the most distinctly charac- 
teristic portion of this layer composed of black argilaceous 
schist containing petrifractions of dictyonémes—a species 
of bryozoes ; and from species of the genus of trilobytes 
called olenus being found in the limestone, this layer has 
received the designation dictyonema schists and olenus 
limestone, It corresponds to the period of the Potsdam in 
the United States. It covers an area of 4,500 square 
kilometres. The argilaceous schist is readily disenti- 
grated, and produces excellent pasture land on the moun- 
tain summits, and in many valleys a rich arable land. 
The same may almost be said of the limestone, the fertility 
of which, from the decomposition of animal remains, is 
considerable. 
Tn some places, as on the west shore of the Christiania 
fiord, at the Skien fiord, to the south of Kongsberg, and 
both banks of the south part of the Miosen lake, the 
layer of argilaceous schist lies immediately on the funda- 
mental rock, 
