Preliminary Notes on Cincinnatian Fossils 
217 
is most distinct posteriorly but frequently reaches the anterior 
margin. Lateral margins of the muscular area divergent as far 
as the anterior end of the exterior pair of diductor impressions, 
and then convergent with a sinuous curvature as far as the ante- 
rior margin of the second pair, between which there is a strongly 
reentrant angle as far as the anterior edge of the adductor impres- 
sions. The adductor impressions are oblong and occupy about 
one-fifth of the width of the muscular area. 
Brachial valve flattened toward the lateral margins, but slightly 
convex on each side of the distinct median depression; the latter 
is narrow near the beak, but widens anteriorly, and produces a 
distinct abrupt curvature in the outline of the shell when viewed 
from the anterior side. The strong and rather wide median ele- 
vation separating the adductor scars broadens posteriorly between 
the crural plates, and supports the cardinal process. The latter 
is divided by a median slit, and often is fairly conspicuous. 
Geological position. Fairmount beds. The types are from the 
quarries in the southwestern part of Hamilton, Ohio, where it is 
abundant. It is much less common at New Trenton, and half a 
mile east of Dillsboro Station, in Indiana. It appears to have a 
very restricted geographical range. 
Fig. id on plate 8 of volume i of the Ohio Paleontology appears 
to represent this species. 
Dalmanella multisecta, Meek. 
This species ranges throughout the Eden formation, into the 
Mount Hope and the base of the Fairmount beds. Two extremes 
have been figured by Meek. The type specimens, illustrated by 
figs. 3^ to 3J on plate 8 of volume i of the Ohio Paleontology^ have 
finer stride, a more circular outline, and a more even convexity 
of the pedicel valve. The other extreme is illustrated by figs, la 
to ic on the same plate, and is characterized by somewhat coarser 
striations, a more triangular outline, and a more angular convexity 
of the pedicel valve, best seen when viewed from the same side 
as the hinge area. 
