Classification of Cambrian Rocks. 307 
ral margin, giving to the surface a cancellated appearance. 
In a few examples, the tubercles are connected, so as to 
give the surface a pitted appearance, like that of Lingula(?) 
favosa and Kutorgina pannula. 
Sculpture of the anterior part on the front and sides in 
the adult consisting of concentric lines of growth, with 
faint, interrupted, radiating striee. 
2. Comparison of Sections in Sweden and New Brunswick. 
The relation of the Paradoxides beds to those beneath 
will be better understood by a comparison of the Acadian 
measures at several localities with the typical Cambrian 
series of Sweden. So nearly alike were the physical con- 
ditions, during this early period of Cambrian time, in those 
{wo countries, that the symbols originally used in New 
Brunswick, to designate the groups of beds, have served to 
distinguish nearly similar sub-divisions in Sweden and Nor- 
way. 
In these sections the base of the Paradoxides beds has 
been taken as the datum-line, and the thickness of the beds 
above and below this horizon, indicated on a scale of 100 
feet to an inch. 
In Sweden, the beds which belong to the lower part of 
the column, and are marked D., are the “ Olenellus beds” of 
that country: those marked a. are the Fucoid and Kophyton 
Sandstones which, by the discovery of I. Schmidt, in Hast- 
ern Russia, are also to be counted as a part of the Olenellus 
beds, since, as already observed, the corresponding beds in 
Russia contain a Mesonacis. The brachiopod (Lingula(?) 
or) Mickwitzia monilifera, which is found with this trilobite, 
and is common to the Cambrian of Russia and Sweden, oc- 
curs in the latter country at the base of the Kophyton sand- 
stone, and this sandstone appears to correspond in position 
to the white weathering sandstone, a, at the base of St. 
John Group in New Brunswick. 
