THE NATUUAL SCIENCE JOUBNAL. 
33 
illustrations so peculiar that no one can 
tell what species he was crediting to 
Rafinesque. The next author, who used 
Strophomena, in such way as to estab¬ 
lish it, was Conrad, who was like Blain- 
ville, in supposing that Rafinesque was 
entitled to the credit of the generic 
name, but he applied it to S. alternata, 
which species was so thoroughly studied, 
described and illustrated that it became 
or was regarded as the typical form at 
the dawn of palaeontological studies and 
has so remained for nearly forty years. 
Why then may not Strophomena alter¬ 
nata be regarded as the type of the 
genus? 
Leptaena planumbona cannot be used 
as the type in any event. The species 
was unknown and undescribed until 1847 
and then it was referred to an old genus. 
And if it was the species which Blain- 
ville illustrated, it would be Strophomena 
rugosa and not Strophomena planum¬ 
bona. Hall’s specific name would have 
no place in science but become a burth- 
ensome synonym. Blainville did not 
undertake to name or describe a genus or 
species of his own, but only to call atten¬ 
tion to one of Rafinesque’s species, and 
if he used a specimen of Leptaena plan¬ 
umbona for his description he was mis¬ 
taken in all respects; for the label writ¬ 
ten by Rafinesque, which is the only 
evidence we have as to the species he 
named, accompanied a specimen of S. 
rhomboidalis in his own coliection. Be¬ 
side it is quite improbable that Rafinesque 
applied the word rugosa to such a shell 
as planumbona, and I cannot think that 
Blainville would have done so either. 
From these statements it is quite clear 
that we may eliminate the w^ork of Blain¬ 
ville from the consideration of the sub¬ 
ject for it can have no bearing on a 
rational conclusion. 
Before proceeding further, it is neces¬ 
sary to call attention to another fact 
connected with this history. There is a 
group of fossils commencing in the 
Trenton fauna and occurring in nearly 
every succeeding geological formation to 
the middle of the Subcarboniferous, that 
is generally referred to the species named, 
in 1769, Conchita rhomboidalis. All 
concede that the fossils in this group are 
congeneric, but some think there are 
several species included under one name, 
and I am one of that number. The dif¬ 
ficulty surrounding any subdivision of 
the group is to find reliable distinguish¬ 
ing specific characters that can be de¬ 
scribed and illustrated. 
Near Richmond and Weisburg, Indiana 
and Lebanon, Ohio, in the upper part of 
the Hudson River Group you may find, 
in the same association, Streptorhynchus 
planumbonum, Orthis insculpta, Stropho¬ 
mena alternata and a species belonging 
to the group of Strophomena rhomboi¬ 
dalis that is very rugose and has been 
locally known as Strophomona rugosa, 
Rafinesque, for many years. If Rafin¬ 
esque obtained his type from this locality, 
as all agree, there cannot be a shadow of 
doubt that the form known here as Stro¬ 
phomena rugosa is the same that he 
named and the same that Hall saw in his 
collection named Strophomena rugosa, in 
his own handwriting. I believe no one 
has attempted to define and illustrate 
Strophomena rugosa from the Hudson 
River Group except the short notice of 
the form under the name of Strophomena 
rhomboidalis, in Ohio Palaeontology, by 
Meek, and the illustration of a form that 
is not characteristic and the locality from 
