THE AGE OF THE TYPE EXPOSURES OF THE 

 LAFAYETTE FORMATION 1 



EDWARD W. BERRY 



Johns Hopkins University, Baltimore 



The following brief communication is devoted to showing the 

 Eocene age of the type-sections of the Lafayette formation in 

 Lafayette County, Mississippi, and also at certain additional 

 localities in northern Mississippi and southwestern Tennessee 

 where fossil plants have been collected by the writer. 



The term Lafayette formation has come in late years to be 

 widely used by American geologists and the volume of literature 

 devoted to its consideration is by no means inconsiderable. 



It is not necessary in the present connection to recite the his- 

 tory of the study of the deposits which have been referred to the 

 Lafayette. It will suffice to recall that the name was proposed 

 by Hilgard 2 in 1891 for those deposits so elaborately described in 

 his Geology of Mississippi 2, as the Orange Sands, and typically 

 developed in Lafayette County. Chief among the students of the 

 Lafayette was W J McGee who extended their occurrence from 

 Mississippi to Pennsylvania on the one hand and as far as Texas 

 on the other. 4 



The writer is not concerned in the present brief note with those 

 deposits in the various Atlantic and Gulf states which have been 

 referred to the Lafayette formation by different geologists. In 

 certain limited areas, however, reliable data have been obtained 

 which may appropriately be announced in the present connection. 

 Thus in the vicinity of Columbus, Georgia, materials classed as 

 Lafayette are Cretaceous in age. Other materials referred to 



1 Published by permission of the Director of the U.S. Geological Survey. 



2 Hilgard, Amer. Geol., VIII (1891), 130. 



3 Hilgard, Rept. on Geol. and Agr. of Miss, (i860), 5-46 (the name Orange Sand 

 was that of Safford, 1856). 



4 McGee, U.S. Geol. Surv., 12th Ann. Rept., Part I (1891), 347-521. 



249 



