Cambrian Rocks in Acadia. sae (| 
ON THE CLASSIFICATION OF THE CAMBRIAN Rocks 
IN AGCADIA. 
By G. F. Marruew, M.A., F.R.S.C. 
[In continuation of a paper in this journal on a Basal Series of Cambrian Kocks 
in Acadia, Vol. II1., No. 1, 1888.] 
Our acquaintance with the Cambrian rocks of HKastern 
North America has now reached that point where it may 
be profitable to suggest the outlines of a general classifica- 
tion of these deposits, in accordance with the scheme laid 
down by the International Congress of Geologists. 
By the term Cambrian, we understand the strata contain- 
ing the Primordeal Fauna of Barrande, both those which 
contain it exclusively, and those which hold its later, modi- 
fied representatives, mingled with the types of the Second 
Fauna ; and also the antecedent forms, which lead up to the 
typical primordeal genera. The base of the system is de- 
fined in the preceding paper, and the summit is best marked 
by the appearance of the early typical graptolites of the 
genera Tetragraptus, Didymograptus, Phyllograptus, Xe, 
These, with the associated trilobites of the Second Fauna, 
form the natural base of the Ordovician System. 
Prof. Jules Marcou expresses a similar view in his limi- 
tation of the formations (terreins) which are included in 
the system called by him Taconic, but which is equivalent 
to the Cambrian, as defined above. His three divisions of 
the system are the Infra-primordeal, the Primordeal, and 
the Supra-primordeal. But, if Mr. Walcott is right in count- 
ing the Georgian Series as Middle Cambrian, the term 
Supra-primordeal hardly expresses the immense develop- 
ment in America of the Potsdam, in which many genera 
are analagous to those of the Second Fauna, Similar genera 
are found in the Regio Ceratopygarum of Angelin in 
Sweden, and in the “Fauna of Hof” in Bavaria, which 
Barrande did not exclude from the Primordeal Fauna. 
At the base of the Cambrian System in Hurope and other 
regions are comparatively barren measures, which, as their 
faunas are made known, will, no doubt, he ound to Primor- 
