68 SEVENTH REPORT—1837. 
all the usual characters and aspect of trap that tabular masses are seen 
distinctly overlying the fossiliferous strata. 
The important fact of the comparatively modern origin of this gra- 
nite, or of its posteriority in date to the strata containing orthocerata 
and trilobites, was announced by Von Buch about 25 years ago. The 
proofs consist in the protrusion of granite veins into the schist and 
limestone, and the alteration of the fossiliferous strata to a considerable 
distance from the line of contact with the granite, the limestone being 
turned into white marble, and the schist into Lydian stone, riband 
jasper, and sometimes into mica-schist, of which I saw one striking 
example at Grorud, N.E. of Christiania. Traces of fossils are not 
unfrequently discoverable in some of the crystalline and altered rocks 
of the transition formation, so that the actual conversion of the latter 
into metamorphic strata is unequivocal. 
Large mountain masses of the granite come into contact with dif- 
ferent members of the transition series, both calcareous and argilla- 
ceous, and the granite sends veins into all of them, and variously 
modifies their mineralogical texture. The fossiliferous strata are also 
seen intersected by the granite, sometimes in the direction of their 
strike, and sometimes at right angles to it; the stratified rocks being 
in all cases more or less changed at the point of junction. The same 
modern granite comes frequently into contact with gneiss, the most 
ancient formation of this district, and sends veins into the gneiss, or, 
in some cases, passes gradually into it, precisely in the same manner as 
in Scotland and other countries. 
There is, indeed, no feature in the geology of this part of Norway 
which appears to me so full of interest, as the relations of the granite 
and gneiss at their junction, when the wide difference of epoch which 
must have separated the origin of the two rocks is considered. I shall 
therefore add a few words on this subject. 
The gneiss is the oldest rock in the country. Next in age are the 
transition strata, corresponding to part of the Silurian formations of 
England; but as these fossiliferous strata rest unconformably upon 
the gneiss, the last-mentioned rock had evidently undergone great 
disturbances before the sedimentary deposits were gradually thrown 
down upon it. The edges, moreover, of the inclined strata of gneiss 
had undergone aqueous denudation, and had been polished and scored 
by attrition before the unconformable transition beds were superim- 
posed. This scored and polished surface is seen occasionally on the 
removal of the newer or fossiliferous beds. As the granite, therefore, 
was introduced last of all in the order of time, there had intervened 
between the origin of the gneiss and granite, 1st, the period when the 
stratification of the gneiss was disturbed, 2dly, the period of its denuda- 
tion, and, 3dly, the time during which the transition beds were gradually 
formed in a sea inhabited by a great variety of organic beings. Yet 
the granite produced after this long interval is often so intimately 
blended with the ancient gneiss at the point of junction, that it is 
impossible to draw any other than an arbitrary line of separation between — 
them; and where this is not the case, tortuous veins of granite pass 
