THE 
AMERICAN GEOLOGIST 
Vol. II. JULY, iSSS. No. i. 
ON PSAMMICHNITES AND THE EARLY TRILOBITES OF 
THE CAMBRIAN ROCKS IN EASTERN CANADA. 
BY G. F. MATTHEW. 
In this part of the continent there are several series^ of rocks 
which may properly be referred to the Cambrian system. 
The following article refers to two of these and describes 
some of the most noticeable features of their faunas. 
A. Etchiminlau Series. 
This the oldest of these series is not known to have any trilo- 
bites; nor have animals of this order been found in the rocks 
which in Wales and Norway are supposed to be of equivalent 
age. Throughout its whole thickness organic remains are 
scanty, or are so small, or obscure, as not to be readily observed. 
In traversing the outcrojDs of its measures one is at times 
arrested by the abundance of worm burrows, casts and tracks, 
indicating the existence of abundant life of a certain kind. 
These tracks and casts are found in the very oldest beds which 
are capable of preserving the imprint of organic remains; they 
occur in sandstones and shales immediately above the conglom- 
erate at the base of the series. This conglomerate, about 60 
feet thick, rests upon amygdaloidal greenstones, which in 
the report of the geological survey of Canada are referred to 
the Huronian system. 
About two hundred feet higher in the series there are fine 
1 By this term the writer designates the grand divisions of a geolog- 
ical system marked by a distinctive fauna and usually separated from 
the series above and below by unconformities. Thus there are in this 
region 3 series of Cambrian rocks, 2 of Ordovician, i of Silurian, 2 of De- 
vonian, 3 of Carboniferous. 
