SPIRIFERiE OF THE CHEMUNG GROUP. 
£43 
sinus, are conspicuously marked by fine regular radiating striae, and, 
in rare examples, these have been observed to be cancellated by con¬ 
centric striae. 
Little is known of the interior of the shell, beyond the presence of 
strong teeth and straight diverging dental lamellae. 
The species presents considerable variety in its form and proportions; but there 
is usually little difficulty in distinguishing it by the external characters, from any 
other species in this formation. In its more rotund forms, it approaches the 3. 
granulifera; but the presence of longitudinal striae may usually be recognized 
in the casts, while the broad rounded mesial fold withght a depression, is a dis¬ 
tinguishing feature. 
Geological formation and localities. This species has been found in Schoharie 
and Delaware counties (New-York), several hundred feet above the base of the 
Chemung group. Fine robust specimens occur hear Cortlandville in Cortland 
county, and a more delicate variety in the greenish shales north of Elmira. The 
stronger forms, with extended cardinal angles, occur on Cayuta creek in Tioga 
county. 
Spirifera disjuncta. 
PLATES XLI & XLII. 
Spirifera disjuncta : Soweeby, Trans. Geol. Society, 2d series, Vol. v, pi. 63, f. 8; pi. 64, f. 12, 13.1840. 
« calcarata: Id. Ib., pi. 63, f. 7. 
•• extensa : Id. Ib., pi. 54, f. 11. 
<* gigantea : Id. Ib., pi. 55, f. 1 - 4. 
>< inornata: Id. Ib., pi. 53, f. 9. 
•« protensa : Phillips, Pal. Foss, of Cornwall, Devon & West-Somerset, pa. 69, pi. 28, f. 118 
<< calcarata & S . disjuncta : Id. Ib., pi. 29, f. 128, 129. [1841. 
«* disjuncta : Id. Ib., pi. 30, f. 129. 
«« gigantjea : Id. Ib., pi. 30, f. 130. 
«« grandceva : Id. Ib., pi. 30, f. 131. 
« distans : Phillips (not Soweeby), Ib., pi. 29, f.,127. 
“ verneuili :■ Muechison, Bull. Soc. Geol. France, Vol. 11* pa. 252, pi. 2, f. 3. 1840. 
*< archiaci : Id. Ib., pi. 2, f. 4. 
«« lonsdalei : Id. Ib., pi. 2, f. 2. ' [1845. 
Spirifer disjunctus : Muechison, De Veeneuil and Keyseelino, Geol. Russia, Vol. 2, pa. 157, pi 4, f. 4 
<« archiaci : Id. Ib., pi.'4, f.5. 1845. [1845. 
<« murchisonianus* : De Koninck, De Veeneuil & Keyseelino, Geol. Russia, Vol. 2, pi. 4, f. 1. 
# I have cited the synonymy to a great extent from Mr. Davidson’s British Devonian Brachiopoda, 
where the Spirifera murchisoniana ( De Koninck) is given as one of the synonyms of S', disjuncta. 
I have not observed the explanation which allows this species to be a synonym of S. disjuncta, and at 
the same time a Cyrtia, Oyrtina (Davidson, Quarterly Geological Journal, Vol. ix, pa. 355, pi. 15, 
f. 6 - 9); but it appears to me that the species figured in the Geology of Russia is distinct from the 
Chinese specimens figured by Mr. Davidson. 
