474 ADDRESS OF T. STERRY HUNT. 
clusion that these limestones instead of being older, were really 
newer than the Olenellus beds, and that the-apparent order of suc- 
cession was, contrary to the supposition of Emmons, the true one. 
This conclusion was still farther confirmed by the evidence ob- 
tained in 1868 by Mr. Billings, who found in that region a great 
number of characteristic species of the Levis formation, many of 
them in beds immediately above or below the white marbles,* 
which latter, from the recent. observations of the Rey. Augustus 
Wing in the vicinity of Rutland, Vermont, would seem to be 
among the upper beds of the Potsdam formation. Thus while 
some of the Taconic fossils belong to the Potsdam and Utica 
‘formations, the greater number of them, derived from beds sup- ` 
posed to be low down in the system, are shown to be of the age 
of the Levis formation. There is, therefore, at present, no evi- 
dence of the existence, among the unaltered sedimentary rocks of 
the western base of the Appalachians in Canada or New England, ` 
of any strata more ancient than those of the Champlain division, 
to which, from their organic remains, the fossiliferous Taconic 
rocks are shown to belong. 
Mr. Billings has, it is true, distinguished provisionally what he 
has designated an upper and a lower division of the Potsdam, and 
has referred to the latter the Red sandrock with. the Olenellus 
slates of Vermont, together with beds holding similar fossils at 
Troy, New York, and along the straits of Bellisle in Labrador and 
Newfoundland ; the upper division of the Potsdam being repre- 
sented by the basal sandstones of the Ottawa basin and of the 
Mississippi valley. In the present state of our knowledge of 
the local variations in sediments and in their fauna dependent on 
depth, temperature and ocean currents, Billings, however, Con- 
ceives that it would be premature to assert that these two types of 
the Potsdam do not represent synchronous deposits. 
The base of the Champlain division, as known in the Potsdam 
formation of New York, of the Mississippi valley and the Appa- 
lachian belt, does not, however, represent the base of the paleozole 
series in Europe. The Alum slates in Sweden are divided into 
two parts, an upper or Olenus zone, and a lower or Conocoryphe 
zone, as distinguished by Angelin. The latter is characterized by 
* Amer. Jour, Sci TI, xlvi, 227 
t Report Geol. of Canada, 1863-66, p. 236. 
