Figure 1. Precambrian to Lower Ordovician fossils from Missouri.
A-C: Early, primitive cephalopods.
A: Dakeoceras sp., one of the earliest cephalopods,
B: Monogonoceras magnisiphonatum, Roubidoux Formation.
C: Pachendoceras huzzahense, early straight cephalopod,
lowermost Ordovician, Gasconade Formation.
D, E, K, M, N: Problematic plated mollusks, Hemithecella sp.
F, J, L: Monoplacophorans.
F: Hypseloconus bessemerense.
G: Group of Hypseloconus and snail-like Scaevogyra.
H, J: Gasconadeoconus sp., Lower Ordovician, Gasconade Formation.
I: Proteroconus (Protoconus) eminense, one of a number of small
curved monoplacophoras found in the Eminence Formation.
K: One possible reconstruction of hemithecellid with sixteen valves.
L: Proplina cornutiformis, a spoon-shaped monoplacophoran showing
distinctive multiple scars characteristic of monoplacophorans.
0: Left-hand-coiling gastropods, Lecanospira compacta,
Roubidoux Formation, Lower Ordovician.
P: Dicellomus sp., a primitive brachiopod, Lamotte Sandstone,
Middle Cambrian, St. Francois Co.; the oldest animal fossil
Q: Matthevia sp., internal mold of a single valve of this problematic
mollusk showing equal sized "pockets" characteristic of Ozark
forms, Upper Cambrian.
R: Ozarkcollenia, a distinctive stromatolite associated with bedded
volcanic ash layers (bedded tuffs), the oldest known fossil from
Figure 1 Figure 2 Figure 3 Figure 4
Publication: Missouri Fossils
Missouri Fossils: Menu
By: Bruce Stinchcomb