24 
PALEONTOLOGY OF NEW YORK. 
Lower Helderberg fauna we have but the single species, S. concinnus. Hall; in 
the Oriskany sandstone, S. arenosus, Conrad; in the Corniferous limestone, 
S. unicus, Hall (= S. arenosus), S. Grieri, Hall, and S. divaricatus, Hall. The last 
named species is the only representative of this type of structure in the 
Hamilton faunas, but from the upper Devonian onward the species multiply 
rapidly, becoming most abundant and varied in the different faunas of the lower 
Carboniferous and continuing until the close of palaeozoic time. The key-note 
to the time value of the Aperturati was suggested by De Verneuil, who 
divided them into two subsections, “ the first including species with fine, not 
dichotomous plications, all of which belong to the Devonian system ; the second 
including those with broad [simple] plications or those which have the plica¬ 
tions fine and always dichotomous. Spirifers of the last division are all 
Carboniferous or Permian.”* With some reservation this statement is emi¬ 
nently true of the American Aperturati, with which alone in the following 
classification we have to deal. 
(a) Disjiinctus-type. Forms with well developed fold and sinus, elongate 
hinge and elevated cardinal area; lateral plications simple, median plications 
dichotomous or intercalary. 
Spirifer arenosus, Conrad, Oriskany sandstone. 
Spirifer unicus. Hall, Corniferous limestone. 
Spirifer Whitneyi, Hall, Lower upper Devonian. 
Spirifer disjunctus, Sowerby,f Chemung group. 
In the higher Chemung sandstone of Alleghany and Cattaraugus counties, 
N. Y., there is a well defined variety of this species which is of not uncommon 
occurrence. It is distinguished by a conspicuous median sulcus on the fold 
and has been well figured in Paleontology of New York, Volume IV, pi. xli, 
figs. 10-16. We propose to distinguish it by the varietal term sulcifer. 
* Geologie de la Russie de I’Eui’ope, p. 126,1845. 
t A preference is frequently expressed by the Continental wiitei’S for the term S. Verneuili, applied to 
this species by Muuchison in 1840. In regard to the priority of these names, both introduced in the same 
year, Murchison has said in the 3d edition of his “ Siluria” (p. 422, 1859): “ Von Dechrn and his associates 
have used the name given by myself in honor of my friend De Verneuil to the Spirifer which abounds in 
the same stratum [Verneuili-shales] in the Boulonnais. It is, however, the Sph’ifer disjunctus, having been 
previously named by Sowerby.” 
