56 
OfSmetGn 
tr> m m. 
Geological Survey, Canada. 
Figure 2. Paracadoceras harveyi sp. nov,; width of umbilicus and thickness of whores 
expressed as fractions of the diameter. Umbilicus of holotype shown by a 
broken line; whorls of holotype by a solid line; continuations of curves, based 
on topotypes, by a dotted line. 
Locality. Zone of Cadoceras hrooksi, on Deer creek one-quarter mile 
from its mouth, west side of Harrison lake. 
Name. After Eobert Valentine Harvey. 
Genus, Cadoceras Fischer 1882 
The North American forms of this genus differ somewhat from the 
European, but not enough to warrant separation. The young are very 
similar to those of Paracadoceras and other genera from North America 
and the Arctic regions as yet unnamed. It is, therefore, quite unsafe to 
name a form of less than 45 or 50 mm. diameter unless the development 
curves of several features show that the specimen is mature. Much 
revision of the Cadoceratoids is necessary, and it is among Arctic faunas 
that this can be done. Probably in the Arctic Jurassic is to be found the 
early history, as yet unknown, of the great Cardioceratid family. 
Two Alaskan and one new species of Cadoceras were found at Harrison 
lake. 
Cadoceras caiostoma Pompeckj 1900 
Figure 3 
1900. Pompeckj : Verhandl. Kais. Euss. Min. Gesell. St. Petersburg, 2 te 
Ser., Bd XXXVIII. 
