15 
THE LOWER SILURIAN ROCKS REST ON GRANITIC GNEISS. 
morphism, we now allude to them merely to show, that although quite alive to 
their value (and our account of the Ural chain will, we trust, sufficiently prove 
this), we still see a clear distinction between such palaeozoic changes and a pre- 
vious metamorphism of the azoic rocks. 
But if the examination of Norway alone sufficed to lead us to entertain this opi- 
nion, we were still more fortified in it by the survey of Sweden, to the considera- 
tion of which we now proceed. 
Silurian Rocks of Sweden and their relations to the older Crystalline Rocks. — In 
the following short outline of some prominent features of the geology of Sweden, 
we will first describe the relations of the Lower Silurian group to the subjacent 
crystalline rocks, as they appeared to us in a traverse from Gottenburg to Stock- 
holm 1 , and will afterwards advert to the fossiliferous distinctions of the Upper 
Silurian group of Gothland. 
In the hills of Hollaberg and Hunneberg, to the east of the Falls of Trolltuetten, 
which are covered by a thick mass of trap rock (basaltic greenstone), one subordi- 
nate member only of the Silurian series is visible, namely, the alum-slate ; but no one 
who knows from numerous other sections, that this band is very near the Silurian 
base, can glance his eye over the lower adjacent lands, all composed of gneiss and 
granitic rocks, or look up from the latter as they appear on the banks of the 
river, near the Falls of Trollhsetten, without being convinced, that the horizontal 
band of black schistose Silurian rock lies above the crystalline granitic rocks of 
the low country, though the absolute junction of the two is hidden by a talus of 
detritus. 
Advancing to the next Silurian oasis at Kinnekulle and the hills of Billingen, 
the same general relations, of a low surrounding country of gneiss and granite, to 
high tabular plateaux of horizontal Silurian strata, usually capped by trap, present 
themselves to the traveller. In ascending the hills of Kinnekulle, from the flat 
gneissose country of Lidkoping, he is no sooner above the low level of those crystal- 
line rocks, than he meets with a terrace composed of quartzose sandstone, already 
mentioned as frequently forming the lowest Silurian stratum in Scandinavia. This 
rock, here arranged in beds from a few inches to a foot and a half thick, is light- 
1 In this journey Mr. Murchison was accompanied by that excellent naturalist. Professor Loven of 
Stockholm, through whose acquaintance with the country, and references to the works and map of Hi- 
singer, it was easy to select the points for examination by which the question of true protozoic succession 
could be best determined. 
