STRATA IN CONTACT WITH GRANITE. 
581 
PossiliferoRS Strata rendered metamorphic by intrnsi’^e Mass¬ 
es of Granite. —In the southern extremity of N^orway there is 
a large district, on the west side of the fiord of Christiania, 
which I visited in 1837 with the late Professor Keilhau, in 
which syenitic granite protrudes in mountain masses through 
fossiliferous strata,’land usually sends veins into them at the 
point of contact. The stratified rocks, replete with shells 
and zoophytes, consist chiefly of shale, limestone, and some 
sandstone, and all these are invariably altered near the gran¬ 
ite for a distance of from 50 to 400 yards. The aluminous 
shales are hardened, and have become flinty. Sometimes 
they resemble jasper. Ribboned jasper is produced by the 
hardening of alternate layers of green and chocolate-colored 
schist, each stripe faithfully representing the original lines 
of stratification. Nearer the granite the schist often con¬ 
tains crystals of hornblende, which are even met with in 
some places for a distance of several hundred yards from the 
junction; and this black hornblende is so abundant that 
eminent geologists, when passing through the country, have 
confounded it with the ancient hornblende-schist, subordinate 
to the great gneiss formation of Norway. Frequently, be¬ 
tween the granite and the hornblende-slate above mentioned, 
grains of mica and crystalline feldspar appear in the schist, 
so that rocks resembling gneiss and mica-schist are produced. 
Fossils can rarely be detected in these schists, and they are 
more completely effaced in proportion to the more crystalline 
texture of the beds, and their vicinity to the granite. In 
Fig. G23. 
Ground-plan of altered slate and limestone near granite. Christiania. The arrows 
indicate the dip, and the oblique lines the strike of the beds. 
some places the siliceous matter of the schist becomes a 
granular quartz; and when hornblende and mica are added, 
the altered rock loses its stratification, and passes into a 
kind of granite. The limestone, which at points remote 
