CAMBRIAN OF SWEDEN AND NORWAY. 
489 ' 
Cambrian of Sweden and Norway —The Cambrian beds of 
Wales are represented in Sweden by strata the fossils of 
which have been described by a most able naturalist^ M. An¬ 
gelin, in his “ Palseontologica Suecica ” (1852“-’4). The “alum- 
schists,” as they are called in Sweden, are horizontal argilla¬ 
ceous rocks which underlie conformably certain Lower Silu¬ 
rian strata in the mountain called Kinnekulle, south of the 
great Wener Lake in Sweden. These schists contain trilo- 
bites belonging to the genevdi, JParadoxides^ OlenuSj Agnostiis^ 
and others, some of which present rudimentary forms, like 
the genus last mentioned, without eyes, and with the body 
segments scarcely developed, and others, again, have the 
number of segments excessively multiplied, as in Paradox- 
ides, Such peculiarities agree with the characters of the crus¬ 
taceans met with in the Cambrian strata of Wales ; and Dr. 
Torell has recently found in Sweden the Paradoxides HicJcsiiy 
a well-known Lower Cambrian fossil. 
At the base of the Cambrian strata in Sweden, which in 
the neighborhood of Lake Wener are perfectly horizontal, 
lie ripple - marked quartzose sandstones with worm-tracks 
and annelid borings, like some of those found in the Harlech 
grits of the Longmynd. Among these are some which have 
been referred doubtfully to plants. These sandstones have 
been called in Sweden “fucoid sandstones.” The whole 
thickness of the Cambrian rocks of Sweden does not exceed 
300 feet from the equivalents of the Tremadoc beds to these 
sandstones, which last seem to correspond with the Long¬ 
mynd, and are regarded by Torell as older than any fossilif- 
erous primordial rocks in Bohemia. 
Cambrian of the United States and Canada {Potsdam Sand¬ 
stone). —This formation, as we learn from Sir W. Logan, is 
VOO feet thick in Canada; the upper part consists of sand¬ 
stone containing fucoids, and perforated by small vertical 
holes, which are very characteristic of the rock, and appear 
to have been made by annelids (Scolithns lineari^. The 
lower portion is a conglomerate with quartz pebbles. I have 
seen the Potsdam sandstone on the banks of the St. Law¬ 
rence, and on the borders of Lake Champlain, where, as at 
Keesville, it is a white quartzose fine-grained grit, almost 
passing into quartzite. It is divided into horizontal ripple- 
marked beds, very like those of the Lingula Flags of Brit¬ 
ain, and replete with a small round-shaped Obolellaj in such 
numbers as to divide the rock into parallel planes^ in the 
same manner as do the scales of mica in some micaceous 
sandstones. Among the shells of this formation in Wiscon¬ 
sin are species of Lingula and Orthis^ and several trilobites 
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