ABSTRACT

Although hundreds of species of cheilostome Bryozoa have been described from Cretaceous rocks in Europe, only 19 species have been reported from deposits of similar stratigraphic position in North America.

Sixteen species were reported by Canu and Bassler (1916) from the Ripley formation (Navarro) at Coon Creek, Tennessee; two species were described from the Fort Worth limestone (Washita) in Texas, one by Cheetham (1954), the other by Dighton Thomas and Larwood (1956); and a single species was described by Butler and Cheetham (in press) from Saratoga equivalent (Navarro) on a Louisiana salt dome.

Cheilostome bryozoans have relatively short stratigraphic ranges and have been used extensively as "index" fossils in European Cretaceous rocks (Lang, 1920, 1921; Voigt, 1930). That they are potentially as valuable in Gulf Coast stratigraphy has been indicated by the occurrence of Rhiniopora in rocks of Companion and/or Maestrichtian age in Europe and North America (Butler and Cheetham, op. cit.).

With the exception of the remarkably preserved Coon Creek fauna, American Cretaceous cheilostomes occur as incrustations on Ostrea and Inoceramus valves and echinoid plates. Perhaps closer scrutiny of macrofossils ordinarily discarded in field investigations will result in discovery of new bryozoan material for biostratigraphic research.

Table 1. Numbers of genera of cheilostome Bryozoa described from Cretaceous deposits.

1. Published with permission of the State Geologist, Louisiana Geological Survey.

End_of_Record - Last_Page 127-------