254 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
Others who are amateurs. Tn this way a considerable fund of 
knowledge has been accuinnlated, which helps to a better under- 
standing of the problems involved in the study of the Cambrian 
rocks. 
For a thousand miles along the Atlantic coast of North 
America the Cambrian sediments show a remarkable uniformity, 
both in the composition of the materials that form the strata, and 
in the similarity of the succession of members of which these 
stratified deposits are composed. 
The same physical causes appear to have operated with much 
uniformity throughout Cambrian time along this coast from 
^Massachusetts to Newfoundland, giving rise to a parallel series 
of strata in all the undoubted Cambrian districts. 
As the following remarks are based on the conditions in ex- 
plored Cambrian areas, it may be said that these are five in 
number, viz., Eastern Massachusetts, Southern New Brunswick, 
the Southeastern side of Nova Scotia, Cape Breton Island, and 
the peninsula of Avalon, in Newfoundland.'*' 
( )f the Cambrian age of portions of the rocks that have been 
referred to this system in Nova Scotia, some doubt may be express- 
ed, for though large areas in that province have been referred to 
the Cambrian, and have been closely studied by capable geolo- 
gists, no distinctively Cambrian fossils have been found. And 
the enormous thickness claimed for the quartzites would seem to 
imply that their base would have come within the region of 
severe metamorphism, if not of fusion, since their deposition. 
It is far in excess of the known thickness of strata in the undoubt- 
ed Cambrian areas to northwest and northeast of them. Also no 
beds similar to the Basal Cambrian as known in the areas to the 
northwest and northeast, have been found at the base of the Cam- 
brian in the peninsula of Nova Scotia. It seems, therefore, not 
impossible that this Nova Scotia Cambrian may include a part or 
the whole of some more ancient system. 
Confining our attention to the areas where Cambrian fossils 
have actually been found, we note throughout this North Atlantic 
* There is another area in northwestern New Brunswick, but neither the succession of 
members nor the faunas can be fully paralleled with those above named; it is therefore not 
considered in this account. 
