FREE INSTITUTE OF SCIENCE 



TERTIARY FAUNA OF FLORIDA 



scribed are in the collections of the National Museum at Washington, the 

 Wagner Institute, and the Academy of Natural Sciences of Philadelphia, ex- 

 cept where otherwise explicitly stated. 



THE VICKSBURG LIMESTONE. 



This, the lowest member of the Oligocene in our Southern Tertiary series, 

 has been intelligently discussed by Colonel Thomas L. Casey (Proc. Acad. 

 Nat. Sciences of Phila. for 1901, pp. 513-518), and I can add nothing of con- 

 sequence to his exposition. It is to be hoped that he will eventually give a 

 monographic account of the stratigraphy and fauna, for which, by his studies 

 on the spot, he is well prepared. 



Through the census taken by Conrad, with the addition of a few species 

 since described, we find that the molluscan fauna of the Vicksburg horizon 

 comprises about one hundred and twenty-two species, of which one hundred 

 and two are peculiar to it; about ten are found in the Claibornian and Jack- 

 sonian Eocene proper ; and possibly a somewhat larger number in the subse- 

 quent Red Bluff substage, of which I have not data to give an adequate dis- 

 cussion at the present time. 



Of the restricted Vicksburg fauna some fifteen species are known to persist 

 into the Ocala limestone or nummulitic horizon, but as the fauna of the latter 

 is only imperfectly known, the real number of Vicksburg survivals is possibly 

 a good deal larger. 



In the second division of the southern Oligocene the lower beds contain 

 an imperfectly preserved fauna which has not been adequately studied, and the 

 first horizon of which the fauna is approximately known is that of the Tampa 

 silex beds- This contains about eight or nine Vicksburg species, and in the 

 Tampa limestone, which conformably rests upon the silex beds, only nine 

 Vicksburg species occur. Only two Vicksburg species have been recognized 

 in the Miocene and persist to the recent fauna. 



Colonel Casey, Mr. Aldrich, and others have shown the fallacy of the 

 notion (to which so much confusion may be attributed) that Orbitoides Man- 

 telli is a characteristic fossil of the Vicksburgian. It is true that in the lower 

 division of the Oligocene Orbitoides is frequently very abundant, but not so 

 (according to Colonel Casey) in the typical bed at Vicksburg. Moreover, a 

 glance at the list given under 'the head of the Ocala limestone will show that 

 there are several species of Orbitoides which have generally been more or less 

 confused with one another and which have been identified for the United States 

 Geological Survey by Dr. Bagg. A careful study and much more extended 



