FREE INSTITUTE OF SCIENCE 



1593 



TERTIARY FAUNA OF FLORIDA 



channels between the hummocks which, together with the worn aspect of most 

 of the fossils contained in it, led to the conclusion that the upper portion, if 

 not the whole, of this deposit had been subjected to the action of strong cur- 

 rents (such as affect the present sea-bottom off Cape Hatteras) with the result 

 of mechanically mixing up the fossils, so that the earlier and later deposits are 

 now found irregularly distributed through the marl without regard to age. 

 From this it follows that comparisons based on the total organic contents of the 

 unconsolidated marl are liable to be misleading. 



A careful study of the fossils which had been loaned to Professor Whitfield 

 for use in the preparation of his monograph, and returned by him with identi- 

 fications, confirmed the view above mentioned. 



There are about one hundred species known from the Shiloh marls, of which 

 thirteen per cent, are known in the recent state and forty per cent, are peculiar 

 to these marls. The Chesapeake Miocene of Maryland and Virginia has fifty 

 per cent, of the Shiloh species in common with New Jersey. But the upper or 

 Duplin Miocene of the Carolinas has only eight species in common with Shiloh. 

 Mixed with the typical Chesapeake fossils at Shiloh we find only two of the 

 Alum Bluff species, Sportella WhitHeldi and Panopea WhMeldi. These might 

 perhaps have been expected, or even a larger number, but there is a certain 

 number of species which are unexpected and belong properly to other horizons, 

 such as the Vicksburgian Cardium eversum, the Oligocene Fasciolina Woodii, 

 Mytiloconcha incurva, and Lunatia hemicrypta. Five of these species are 

 known from Chipola, one from St. Domingo, five from the Tampa silex beds, 

 and two from Vicksburg. 



The Shiloh marls occur in patches of limited distribution, and I regard 

 their fauna as containing ten or twelve per cent, of species which normally 

 should not be present in it, and which have come there by mechanical inter- 

 mixture. These species, however, testify to the presence in this vicinity of a 

 contingent from the Oligocene faunas of the south, the sediments of which in 

 New Jersey were removed by denudation or exist only off the coast beneath 

 the sea. 



I have included in my general table the statistics of the Shiloh fauna, the 

 list of which can be found in Professor Whitfield's monograph of the Mollusca 

 and Crustacea of the Miocene formations of New Jersey. 



* Monographs of the U. S. Geological Survey, xxiv., 1894; issued in if 



