Abstract

EDITOR'S NOTE: Dr. Hoffmeister's complete paper is to be published with Dr. L. R. Wilson of the University of Massachusetts as Bulletin No. 32 of the Oklahoma Geological Survey. A previous article on the use of plant and animal microfossils for correlation purposes appeared in the April, 1955 number of World Oil. This paper is entitled "Microfossils Provide New Technique in Exploration." A lead paragraph in heavy print says:

"Minature plant spores and pollen and minute animals found in sediments can be used for (1) age determination (2) zoning formations and (3) indicating favorable environment of deposition."

Regarding (3) it is stated in the paper that by counting microfossils in a group of bore holes from a particular sedimentation unit of the same geological time the approximate location and direction of the shore line may be determined. Studies of bottom samples from the Gulf and along the Atlantic shore have found a variation in the microfossils which show the seaward direction and the change from brackish to marine waters. The results of such studies can be applied to the ancient basins; the variations in the type and number of microfossils can be contoured, and thereby suggest where favorable sedimentation in the basin has occurred and where further study is therefore desirable.

The preciseness of Dr. Hoffmeister's correlations in the coal series over considerable distances and through different facies is a delight. If it can be coupled with a solution of local sedimentary changes in the ancient basins the micro-paleontologist should have a shining future before him.

Fossil spores and leaf cuticles of the Croweburg coal of Pennsylvanian (Desmoinesian) age from nine localities in northeastern Oklahoma are described and statistically treated for stratigraphic correlation. The spore assemblage consists of 13 genera and 48 species. One new genus nine new species and four leaf cuticle types are described. The microfossil flora is similar at all localities in composition and relative abundance. It differs markedly from the underlying Bluejacket coal spore assemblage, and from the overlying Iron Post coal spore assemblage. The Croweburg microfossil flora appears to be correlative with the Colchester coal of Illinois. Spore associations in the bottom, middle, and top thirds of the seam are designated by those genera or species which reach their greatest abundance in those levels. These abundances suggest that the Croweburg floral succession began with the Cirratriradites and Triquitrites maxima, changed to a Laevigato-sporites maxima association in the middle third of the seam, and finally in the top third, Calamospora, Endosporites and Florinites attained their maxima. Calculated measurements based on Carbon 14 studies of peat and reduction of vegetable matter to bituminous coal suggest that approximately 20,000 years were required for the deposition of the Croweburg coal seam.