297] 



B. Wade 



99 



horizon, wood fragments are, however, common. The totality 

 of the evidence seems to indicate that the Coon Creek fauna 

 lived in the agitated waters near the coast of .a low-lying 

 land mass. 



A study of the distribution and variation of the faunas 

 with reference to the character of the sediments in the Rip- 

 ley formation of northern Mississippi and southern Tennes- 

 see shows that the areas so favorable to molluscan life were 





a '.'.*.;.','! '..',' \ '..'/ .'. ''..' "..' '.''..' . . ' .. '. .' '. . .' 



W MUv**y Group. 



T Owl C'rtti ffcriiiT, + N,,tA'rn fflt* 

 17 Mc/fitty Sin<t Mimic, 

 JHFtiTugin,,** City Ho*Un 



I Stlmi CAt2t 



Big Cut 

 S.ln,. r - 



FIG. 2. Section of Upper Cretaceous deposits of McNairy County, 



Tennessee. 



quite local in extent. The sediments bearing such an abun- 

 dance of shells are limited both laterally and vertically in the 

 Ripley strata and do not show a uniform wide range over a 

 large area as is so commonly true of Paleozoic fossiliferous 

 beds. (A diagrammatic section SW-NE across the McNairy 

 County is shown in Fig. 2.) By tracing the Coon Creek 

 horizons southward the plentiful shells disappear leaving in 

 some places a very dark non-fossiliferous clay. Near Larton, 

 McNairy County, the basal Ripley beds are represented by a 

 glauconitic sand which contains branching remains of the 

 so-called fucoid Halymenites major Lesq. This thickness of 



