660723- |69

THIS (3S A REPORT WRITTEN BY ANNEITE C.BEE (DEC ,/470) ON FART
OF THE COLLECTION OF UNIONIOS COLLECTED NWOF CLINTON, (SEE
NOTES TULY 23,/9L 6,

ABSTRACT: A study was made of the unionid mussel shells found on the
surface of the stream bed of the Wakarusa River, northwest of Clinton,
Kansas. Deduction of how closely the assemblage of specimens found
relates to the actual live population at this location is attempted with

little result. on = ae ao pidegesee

INTRODUCTIO® : One of the greatest problems in paleontology is the correlation
of fossil assemblages with their initial living biomes. It is possible
only to infer from the preserved material what the living assemblage was.
The probability that an organism will be preserved as a fossil is slight,
due to transportation of its remains out of its biome, physical and chemical
breakdown of the remains, and chance for burial. These factors are most
important én the oe environment where current is the major control of
position of organisms in the stream channel. This stwdy encompasses a population
of both live and dead unionids found on the surface of a stream bed, before the
burial process has preserved a few individual remains as fossils.

Unionids are a family of the class Pelecypoda of the Mollusca phylum.
They are mussels found in both marine and fresh water (Kansas). They have
two calcareous shells (valves) hich are symm:trical to each other. Unionids
are totally or partially buried in mud throughout their life. Predation

by muskrats is heaviest on adult mussels and by fishes on juveniles.

MATERIALS AND METHODS: The material studied was colledted on July 23, 1366
from the Wakarusa River northwest of Clinton, NE corner of section 15, T. 13 5.,
R.18 E., Douglas County, Kansas. This 460 foot stretch of the river lies
between two permanent, deep pools and is itself shallow and rippled, with

alternately rapidly flowing water in constricted areas and slower moving