TRANSACTIONS OF THE SECTIONS. 69 
_ freely through gneiss, ending sometimes in threads, as if the older rock 
had offered no resistance to their passage. Had I seen such junctions 
alone, and known nothing of the relative age of the gneiss and granite, 
I should have been inclined to suppose that the gneiss had not yet 
been fully consolidated, and had not, perhaps, assumed its complete 
‘metamorphic character at the time when it was invaded by the granite ; 
but this hypothesis is quite inadmissible, fragments of the gneiss having 
been imbedded in the transition strata long before the granite ap- 
peared. The only hypothesis, therefore, that seems to remain to those 
who adopt the Huttonian theory of granite is, to conceive the gneiss to 
have been softened, and more or less melted when the granite was 
introduced. I have before mentioned that the fossiliferous strata 
“occasionally dip towards the granite up to the line of contact; and it 
deserves mention, as a singular phenomenon, and a general one near 
Christiania, that neither the strike nor prevailing dip of the transition 
beds is affected, or seen to vary at the points of union with the granite. 
‘They are altered in mineral character, as before described, and often 
_ become quite metamorphic; but they are not more disturbed there 
_ than elsewhere, and their inclination and bearing remain the same. 
What is still more extraordinary, there are places which I visited with 
Professor Keilhau, where portions of the transition beds, some of them 
only a few hundred yards square, occur completely isolated and sur- 
rounded by granite, and yet continue to preserve their normal dip and 
strike. This phenomenon has been adduced by Professor Keilhau as 
offering, together with many others in the same district, strong grounds 
_ of objection to the Huttonian theory ; for it appears to him impossible 
that the granite can have been injected in a fluid state, or forced into 
the fossiliferous strata without causing more local derangement in their 
dip and strike. 
Without denying the consideration due to this argument, I confess 
_ that its weight was much lessened in my mind after seeing other ap- 
pearances exhibited in certain large dikes of syenite which pierce 
_ through the fossiliferous strata near Christiania. Some of these dikes 
scarcely differ from granite in texture, and are occasionally branched ; 
_ yet the strata at the junction, or even when included between two 
ramifications of syenite, preserve their accustomed dip and strike. 
_ The analogy of such dikes to trappean and volcanic dikes, both in 
_ form and in their relations to the intersected strata, together with the 
- occasional passage of the syenite into common greenstone, leave me 
in no doubt that they are masses and walls of fused matter which 
have filled up fissures opened in the previously consolidated transition 
‘strata. 
Granite. 
