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on Devonian fossils of New York. 47 
authors unite these genera. The Platyceras pyramidatum (Hall) 
resembles the P. hercynicus (Kayser), the P. symmetricus (Hall) 
the P. uncinatus (A. Roemer), and the P. carinatum (Hall);the 
P. zinkeni (A. Roemer). 
It does not appear that there are identical forms common to 
the Devonian strata of America and Europe; but if it be 
impossible to assimilate the species of the two sides of the 
Atlantic, we should nevertheless have a false idea of these 
faunas by neglecting all comparison. The American De- 
vonian species have representatives in the same formation 
in Europe; they are analogous forms, and perhaps geographical 
varieties. This important fact is observed: that the change 
in genera and families has been in a great degree the same 
in the Devonian series of the two continents. Thus the Macro- 
cheilus (Phill.), represented by four species in the Devonian 
of New York, are Devonian forms common in Europe. It is 
the same with the Loxonema (nineteen Devonian species in 
America); the Euomphalus (nine American species); the Pleu- 
rotomaria (twenty-four species) ; the Murchisonia (six species) ; 
the Bellerophon (twenty-four species); and the Turbo (one 
species)» 
) 
B. acutilira (Hall) B. Murchisonia (d’Orb.); B. brevilineatus 
Hall) B. Vernewili (d’Orb.); B natator (Hall) Bo expansus 
(Sow.) ; B. leda (Hall) B. decussatus (Flem.); B. Helena (Hall) 
B. hiuleus (Mart.); B. rotadinia (Hall) B. trilobatus (Sow.); B. 
mera (Hall) B. tuberculatus (d’Orb.) ; Porcellia Herizeri (Hall) 
Porcellia puzo of Europe. 
There are therefore relations between the Devonian faunas 
of the two continents. It is to be noticed also that the genus 
Kuomphalus is divided, in the Paleontology of New York, 
into two sections, having for types the Kuropean Straparollus 
of Montfort and the Phanerotinus of Sowerby ; Professor Hall 
takes from this family the Huomphalus Decewi (analogous to 
our £. Wahlenbergii (Goldf.) to make the type of his new genus 
Pleuronotus, The Bellerophons are as abundant in the De- 
yonlan in America as in Europe; there are five species in the 
Upper Helderberg, fourteen in the Hamilton, and five in the 
