362 Parallelism of the Paleozoic Deposits 
The Orthoceratites, which by their large lateral syphon, empty 
or furnished with a tube in the interior, form a type so remarka- 
ble that Mr. Hall calls them Endoceras,* are equally characteris- 
tic of this system, both in Europe and America, and do not ap- 
pear to have prolonged their existence into the superior Silurian 
epoch. They are as abundant in the Trenton beds as in the Or- 
thoceratite limestones of Sweden and Russia, and we think there 
must be many identical species in the two countries, although 
we have yet recognized but one. 
The Bellerophons date their existence also from the first peri- 
ods of creation, and we find nearly as many of them in America 
as in Europe. The most interesting for us is the B. bilobatus of 
the Trenton limestone, which is certainly the same as that which 
is found in the lower Silurian limestone of Christiana, or in the 
contemporaneous sandstones and schists of Wales. 
With the Trilobites and the Orthoceratites, the Brachiopods, 
by their variety of forms, are of all the fossils of this epoch, those 
which contribute most to give a peculiar stamp to the primitive 
fauna of the globe. The Orthis, the Leptena and the Terebrat- 
ule, are the only ones in America as in Europe, which have ex- 
isted from the earliest times. The other genera, such as Spart- 
fer, Pentamerus and Productus, do not appear until later. The 
Orthis with simple plaits, so distributed through the lower Silu- 
rian beds of Europe, are represented in America by the OQ. trice- 
naria and O. pectinella, Conr.; both of them near the O. calli- 
gramma of Russia and Sweden. The Orthis testudinaria and 
O. Verneuili are equally characteristic of the inferior stage of 
the Silurian system, on both sides of the Atlantic; the Spirifer 
lynx, which we consider as intermediate between the Spirifer and 
Orthis, passes from this same stage as far as the Clinton group, 
and is equally found in England from the Wenlock slates to the 
inferior Silurian beds. Finally, among the zoophytes, the Chate- 
tes Hanus is the only one which is very abundant in eve- 
ry country, without ceasing nevertheless to be characteristic. 
The Stromatopora concentrica and the Ptilodictya lanceolata are 
not found in Europe before the superior stage of the Silurian 
system. 
when we arrive again at fossiliferous beds, that is to say, those 0 
Clinton, the organized creatures have suffered in the succession 
ae whet. os eis luis 
without any doubt, to this is 
{ By the use of the term Trenton limestone in this place, M. de Vernenil in 
mien include not only that limestone, but also the Utica slate and Hudson. 
ver group.—J. H. sine 
* The Orthoceratites bisiphonatum, Sow., of the Caradoc sandstone, belongs, 
type. 
