SWALLOW—DESCRIPTION OF FOSSILS. 657 
meet or intersect in the middle, forming an obsolete mesial 
line where the two sets meet; the spaces between the ceste 
twice as wide as the costa. There are twent i 
space equal to the width of the side, at the place counted. 
The sulcations are marked with obsolete, irregular strie. 
This species has the general appearance of the C. Missou- 
riensis, but may be easily distinguished by the granulations 
of the coste and by the greater number of coste. 
Very rare in the Upper Hamilton Shales at Hannibal and 
other places in Marion county. 
CoNULARIA TRIPLICATA, 0. sp. 
are eight triplicate coste in a space equal to the width of the 
side where counted. 
This beautiful little fossil may be distinguished from all 
others by its peculiar markings. : 
Associated with C. Marionensis in the Upper Hamilton 
Shales in Marion county. 
ConvuLarta Missovriensis, n. sp. 
marked by deep angular sulcations; the acute lateral edges 
subearinated. Surface polished ; each of the four sides acne 
ed by flexuous, high, sharp plications. There are two sets of 
plications on each side ; they commence on or ae aes 
curve towards the base, then partially back, when they 9 
or intersect in the middle, forming an indistinct longitudin 
suleation along the middle of each side; the space between 
the plications is at least twice as wide as the plications. 
Trocuus MrssouRIENSIS, 0. Sp- 
yramidal ; surface high- 
base broad, concave ; 
: ; and below; lower an 
cpt he ate page hte meeting at an acute 
angle ; upper surface slightly concave to fit the under surface 
of the whorl above, and forms with the outer surface an ob- 
