Rules and 31isruJes in ('lassijication. — JIarcon. 47 
The same sj^steiu of strata, with the same composition and 
the same characteristic fossils, extends interruptedly from 
Chaz}^ to Rouse's Point, St. Jean and Montreal, and covers 
the greatest part of Jelfersdn county, state of New York, on 
the right shore of the St. Lawrence river and at the end of 
lake Ontario, and is followed without interruption through 
the state of New York as far as the Mohawk valley. 
During many years the referring of the Phillipsburgh and 
Pointe-Levis group and the Swanton and Quebec city group, 
as defined by me in 1862, to the Calciferous and Utica-Lor- 
rain (or Hudson group) was rather a simple theoretical form- 
ula used by my critics to mean only that they considered it 
impossible to refer those strata to any horizon below the 
Potsdam, on account of some of the fossils found in them. 
At the same time there was a reluctance to question either 
the exactness of the determination of those fossils or of their 
scientific value in classification of strata. The}' were spoken 
of as matter of facts, not requiring descriptions and illustra- 
tion b}' figures of those on which such a correlation with the 
Calciferous and the Hudson was based: a sort of authorita- 
tive S3"nchronism imposed as a creed in American and Cana- 
dian stratigraphy. Eight or ten, a dozen at most, of fossils 
— just the same number of species signalized by Andrew Ram- 
say and Etheridge as passing from the Tremadoc and Arenig 
divisions into the (Jaradoc group in Wales and England — 
some fossils badly determined as the A fops frilinedfus wvong- 
ly referred to as Tridrfhriis heckii, the J//c/'o(/(!>oy<* considered 
as a Triuuclens, and some Brachiopoda, an order of fossils 
more apt to possess foi-ms which pass from one system to an- 
other, are the only true base made use of; a very narrow and 
incorrect view of the paheontoiogical characters established 
by Alexandre Rrongniart. 
But since 1S88 attempts have been repeatedly made to put 
practically in the tabular view of the Champlain system the 
six or eight thousand feet of strata, called and limited by rae 
as the Phillipsburgh and Pointe-Levis group and the Swanton 
and Quebec City group; and curiously enough, although those 
two great groups at the typical places — the vicinity of Quebec 
city and tiie vicinity of Phillipsburgh and Swanton — succeed 
one another in concordance of stratification, one is placed as 
