32 
THE NATURAL SCIENCE JOURNAL. 
And from that year to this or for forty 
years these names have been applied to 
the fossils by all the officers of the Sur¬ 
vey, and used exclusively in the palaeon¬ 
tological Reports of that country, so far 
as I am aware, without exception. 
In the Canadian Naturalist, Vol. V., 
for February, 1860, Billings said : 
“In the Silurian rocks of Canada and 
the neighboring countries there are many 
species or varieties of that group of the 
genus Strophomena of wffiich S. alternata 
may be regarded as the typical form. 
These are all closely related and yet 
exhibit such differences that only those 
naturalists who entertain wide views upon 
the subject of the value and significance 
of specific distinctions, would feel in¬ 
clined to unite them under one common 
name. The forms of this group most 
common in the Lower and Middle 
Silurian rocks are S. alternata, S. incras- 
sata, S. deltoidea, S. camerata, S. teuu- 
istriata and some others to be described 
in this paper.” 
This language was quoted and ap¬ 
proved, in June, 1862, in his Palmozoic 
Fossils, Vol. I., p. 115. And, judging by 
the general Geology of 1863, and all the 
later publications, it has been accepted 
without opposition, in that country, since 
that time. 
It may be stated, that at the very 
commencement of the study of palaeon¬ 
tology, in the United States and Canada, 
the w'ord Strophomena came into general 
use as the generic name for Strophomena 
alternata, even before that common fos¬ 
sil had been described or illustrated, and 
it has been used as the generic name for 
that species almost exclusively ever since. 
It was not long after it had been defined 
and illustrated until it was regarded as 
the typical form of Strophomena, as 
shown by the express language of Bill¬ 
ings and its use in the school text books, 
as appears by Dana’s Manual of Geology 
of 1862, where we find Strophomena 
alternata, Leptsena sericea and Stropho¬ 
mena (Leptinna) rugosa, showing that 
Strophomena rugosa might be a Leptsena 
but not so with S. alternata. 
The name Strophomena was first ap¬ 
plied, without definition or illustration by 
one party to a fossil from America which 
gave to it no vitality as a scientific term. 
Subsequently another author attempted 
to define and illustrate the type under 
the name of Strophomena rugosa but no 
one can tell with certainty from the defi¬ 
nition and illustration what species the 
second author had before him. Authors 
generally have said that it was Stropho¬ 
mena depressa, an European fossil, with 
an older name, and which is said to be a 
synonym, for Strophomena rhomboidal is 
a still older name, that Rafinesque had 
named and Blainville was trying to de¬ 
scribe. Others recently have said, they 
believed it was a fossil belonging to 
another genus and which has been de¬ 
scribed since that time as Leptsena plan- 
umbona and is generally known as 
Streptorhynchus planumbonum, that 
Blainville was trying to describe, and I 
express the opinion that the illustration 
is a better representation of Orthis in- 
sculpta than it is of either of the other 
species. 
Wo cannot receive the generic name 
Strophomena or the specific name rugosa 
from Rafinesque. We cannot take either 
one from Blainville, because he did not 
pretend to be the author of either one, 
but credited them both to Rafinesque, 
and his definition is so obscure and his 
