61 
[Marcou. 
changed the stratigraphic position of the Georgia formation from 
the lower part of the Potsdam group, as he had it in 1886, to the 
upper part of the Potsdam — a strange error for a palaeontologist. 
The Quebec group is placed above the Potsdam, which is not 
really the Potsdam, but the Georgia formation, being far below the 
true Potsdam of New York and the vicinity of Montreal. 
These divisions and denominations are artificial in the extreme 
and the classification is entirely imaginative. The Potsdam does 
not exist anywhere in the whole province of Quebec, except near 
Montreal and perhaps at St. Armand. But we have the Georgia 
formation, well developed from Bic harbor, St. Denis, St. Rock, 
St. Jean, St. Pierre to Livaudiere and the road from Pointe Levis 
to Arlaka which is there in its right and proper place ; below we 
have the St. Albans group of strata containing diorite dikes in the 
area of the Chaudiere and Etchemin rivers ; and above, the Georgia 
is succeeded by the Pointe Levis and the Philipsburgh group, 
forming the whole of Pointe Levis and the greatest part of the isl- 
and of Orleans. 
As to the Citadel hill and city of Quebec group, we have also to 
cross the St. Lawrence to find it in its proper place ; but that divi- 
sion has nothing to do with the Sillery division of the south side 
of the St. Lawrence, as it is recorded in Richardson’s geological 
map. 
It is possible that the dioritic-diabase eruption existed as well 
during the Georgia formation deposit as during the St. Albans 
group ; and if so that is why we do not find any fossils in the area 
of the Chaudiere and Etchemin rivers, the arrival of such material 
from the interior of the earth’s crust having prevented the existence 
of marine animals in that region. 
selwyn’s classification of 1879. 
Mr. Selwyn having succeeded Logan as Director of the Canada 
geological survey, has proposed some alterations and changes in 
the stratigraphy of the province of Quebec. It was during the 
years of 1876, ’77 and ’78, that Mr. Selwyn made explorations 
on the southern side of the St. Lawrence river, and in 1879 he 
published his “ Report of observations on the stratigraphy of the 
Quebec group, etc.” In it, he refers all the slates, or shales, dolo- 
mitic limestone, sandstone and quartzites extending from Vermont 
