ORDOVICIAN FAUNAS. 129 
OPHILETA? sp. undet. 
Among the specimens collected at Columbia are numerous frag- 
mentary examples of a small, depressed, dish-like, coiled shell, with 
a broad, open umbilicus, which may be a member of the genus 
Ophileta. The specimens do not exceed 10 mm. in diameter. 
ECCYLIOMPHALUS SUBELLIPTICA Nn. Sp. 
Plate IV., Fig. 6. 
Description.—Shell loosely coiled, consisting of a little more than 
one volution, which increases gradually in diameter. Cross-section 
of the tube subelliptical in outline, slightly flattened above, sub- 
angular at the inner, upper margin, and rather sharply rounded on 
the periphery. Shell substance rather thick, nearly smooth or marked 
by indistinct lines of growth. : 
The dimensions of an average specimen are: maximum diameter, 
27 mm.; width of outer volution at aperture, 7 mm.; height of same, 
5 mm.; distance between the outer and inner volutions at the aper- 
ture, 2.75 mm. 
Remarks.—In none of the specimens observed is there more than 
about one and a quarter volutions preserved, but the inner extremity of 
the shell is always somewhat blunt, so that some of the older portion of 
the shell may have been removed. The shell resembles H. priscus 
Whitf., from the Beekmantown limestone at Beekmantown, New 
York, but the size of the volutions increases more gradually, and 
none of the longitudinal flutings of that shell have been observed. 
It agrees even more closely with H. multiseptarius Cleland, from 
strata of similar age near Fort Hunter, New York, but lacks the 
strongly-concave, transverse septa of that species. 
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