Figure 1

Figure 1. Precambrian to Lower Ordovician fossils from Missouri.

A-C: Early, primitive cephalopods.
A: Dakeoceras sp., one of the earliest cephalopods,
     Cambrian-Ordovician boundary.
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
     from Missouri.
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
     Missouri.

Figure 1  Figure 2  Figure 3  Figure 4

Publication:  Missouri Fossils

Missouri Fossils: Menu
By: Bruce Stinchcomb