''Review of 'Recent Geological Literature. 133 
and the fossils in question \a ere found near the top of the lower portion. 
Generally speaking these beds may be paralleled in America by the Par- 
adoxides-bearing strata found in different places, as at Braintree, Mass., 
St. Johns, New Brunswick, and eastern Newfoundland, &c. But it is 
doubtful if any beds as old as the Lower Cambrian or Llanberis slate are 
yet known in the United States or in Canada. 
C. viola is about three inches long by one inch and three quarters wide, 
showing that the trilobites of that early day were not the smallest of 
their kind. 
The fauna of the Longmynd or Lower Cambrian group of Britain is 
thus summed up by the author. 
Sponges 1 I Brachiopods 2 
Ostraeods 2 Pteropods 2 
Trilobites 7 | Annelids 3 
Making a total of only se\enteen or with the new trilobite eighteen 
species. 
There is some discord between the various statements in this paper. 
In the table the number of trilobites is said to be seven, whereas eight 
ai-e enumerated above by name. Again in a footnote the whole number 
of trilobites known from the Cambrian rocks is given as eighty-five 
whereas in the table the total is loi. There is nothing to show that dif- 
ferent localities are intended so that the inference is natural that the 
results relate to all. 
Dr. Traqiiair of Edinburgh discusses in the Geological Magazine for 
May, several points in the relations of the relics of fossil fish to one 
another. 
He is inclined to think that the evidence does not bear out the opinion 
he formerly advanced that Ctenacanthiis and Cladodus were the spine and 
tooth of the same fish, and that Hybodns was to be placed with them. 
He now believes that Hybodns is distinct from both and that further 
knowledge will distinguish Cladodus from Ctcnacanthus. He dissents 
from Mr. Carman's opinion that in the recent and recently discovered 
Japanese ii\\a.Y'kC/ila»tydosrlac/iusaii<>ui>iri/s — which is spineless — we have 
a modern Cladodont. 
He then shows that one species at least of " Ilelodus and of Lof/iodus 
belong to the mouth of the same fish, which is a Pse/l/odus" and that the 
anterior teeth of Psepliodns and of Cochliodus are indistinginshable gener- 
ically from Helodus. 
After describing a new spine, Oracantlnis armigerus, relying on the 
asymmetry of this genus, he maintains that Oracanthus is not a fin or 
tail-spine but the postero-lateral termination of the headshield of some 
fish covered with a Cephalaspidian buckler. " I think," he adds," "there 
can be no further doubt that the portion of Oracanthus spines is on the 
head of a selachian and not on the tail of a placodermic ganoid." 
Geological and Natural History Survey oj Canada; Annual report^ (\ol. 
ii,) i886, Montreal, $2.00. Alfred R. C. Selvvyx, Director. This val- 
uable document embraces thirteen parts, devoted to as many portions of 
