Recent Discoveries in the St. John Grou}'). 
101 
different types. Tlie bivalve crustaceans have a fair representation ; 
those of the underlying band are not found, but new species appear, 
including those of the genera Primitia, Leperditia, etc. The trilobites 
are represented by the most ancient genera: — Agnostus has four 
species. Microdiscus two, Ptychoparia five or more, Conocoryphe 
three, an ancient type of Ctenocephalus one, and Paradoxides four ; 
all four of this last genus have continuous eyelobes. 
Passing to the beds of the next band, viz., a change in the 
fauna is at once apparent, though a connection with the preceding- 
fauna is maintained by the presence of the undescribed sponge, all 
the pteropods, and of two familiar forms of brachiopods — Linnars- 
sonia and Acrothele ; there are also varieties of the Agnosti, the 
Ptychoparse, and of Protospongia (?) of band c. On the other hand 
quite a number of new species appear at this horizon, among which 
may be named a Dendrograpsus (?), another Lingulella (?) and two 
new species of Stenotheca. Two worm-casts and new species of 
bivalve crustaceans also come in at this horizon. Among the 
trilobites also there are new species. The Agnosti have four ; 
Microdiscus exhibits a new form closely allied to 31. punctatus.^ 
Salter. Among the Ptychoparise some species now appear for the 
first time, and Solenopleura has a representative. A Paradoxides 
with shortened eyelobes has left abundant fragments in these 
measures ; it is a species which by its pleural spines, pygidium and 
hypostome is allied to P. Bohemicus of Europe. 
This new fauna consists largely of forms similar to those of the 
Menevian Group, and is chiefly remarkable for the great abundance of 
Pteropods, Microdisci and Agnosti, and for the presence of a Paradox- 
ides with shortened eyelobes. So far as they are at present known, each 
of these successive sub-faunas has an individuality of its own ; that in 
band h contains forms the most remarkable for novelty ; band c is 
notable for the variety of sj^ecies it contains, and band d for the 
abundance of individuals of many of the species. The beds of the 
band h may be said to have been deposited on a sandy shore, those 
of c on a muddy shore, and those of d in deeper and more tranquil 
waters. Volcanic action in the vicinity of the St. John Basin seems 
to have been dormant during the time when the beds of band a were 
laid down, but awoke into activity during the period when the strata 
of b were deposited, and gradually died away while the olive grey 
mud beds of c were formed. The time when these successive faunas 
