AECTIC ORDOVICIAN AND SILURIAN CEPHALOPODS 257 
crinoid stems are common in the Canadian strata of Bear Island. 
Moreover, fragments of crinoid stems are common also in some 
of the rock specimens belonging to the Black River strata of 
Bear Island. 
In view of the wide distribution of Black River strata in Arctic 
areas it is interesting to observe that only three species of crinoids 
have been described so far from American Black River strata, 
and all of these were found in the northern part of the Mississippi 
embayment. These 3 species are Carabocrinus dicyclicus (Sarde- 
son) from the Decorah of St. Paul, Minnesota, and of Ellsworth, 
Wisconsin; Cremacrinus punctatus Ulrich from the Decorah of 
Minneapolis, Minnesota; and Porocrinus pentagonius Meek and 
Worthen from the Platteville of Dixon, Illinois. In the matrix 
of the Black River strata in the Boothia Felix-King William 
Land area and from the Cape Chidley area in northern Labrador, 
only very depauperate stems of crinoids or cystids occur. Un- 
fortunately it is not known on what basis the Bear island Cana- 
dian and Black River stems were interpreted as crinoidal rather 
than as cystidean. That cystidea are of much earlier origin 
than crinoidea has long been known. 
Among the Silurian faunas invading North America by way 
of the Mississippi embayment are the Brassfield, typical St. 
Clair, Osgood, Rochester, Waldron, and Brownsport, while the 
Waukesha, Racine, Lockport, and Guelph represent invasions 
from the north. (Ulrich, ibid., pp. 558-561). Regarding the 
migration of Gotlandian faunas from Scandinavian-Baltic areas 
across the Arctic into the Racine seas of Wisconsin and adjacent 
Illinois, it is unfortunate that our knowledge of Niagaran faunas 
in Arctic areas still is so inadequate. In my opinion, no equiva- 
lent of a Gotlandian fauna has been recorded so far in American 
Arctic regions. 
From Oflley Island, at the mouth of Petermann’s Fjord on 
the west coast of Greenland, at 81°16' north latitude, came the 
forms described and figured by Foord as Orthoceras arcticum 
Foord and Orthoceras darwini Billings. The first of these is a 
cyrtoceraconic shell closely allied to an undescribed form in the 
Racine of the Wisconsin area, while the second is the familiar 
