FREE INSTITUTE OF SCIENCE 



1565 



TERTIARY FAUNA OF FLORIDA 



crop has made it easy for any tourist to search the beach, and it may be said 

 that the days of profitable collecting at Ballast Point are over, as the supply 

 of pseudomorphs is dependent upon the slow disintegration by sea and air of 

 the limestone in which they are contained. The same rock in a more solid and 

 refractory condition extends under the channel ofif the point, and the engineer- 

 ing operations for deepening this channel brought up large masses of it, from 

 which a few species were obtained at the cost of much labor. Probably boiling 

 pieces of the rock in hydrochloric acid might result favorably. > 



About forty-nine per cent, of the species in the Orthaitlax bed are peculiar 

 to it, and very few of the more minute forms which should be present in such 

 a fauna are known. The relations of the fauna are most intimate with that 

 of the Oligocene beds above it, the Orbitolite or Tampa limestone, the Chipola, 

 and the Oak Grove sands. With either of these the percentage of species 

 common to both is more than twice as great as with any of the beds below, such 

 as the nummulitic, the Peninsular limestone, or the Vicksburg. But it must 

 be admitted that the faunas of all these, except the last, are very imperfectly 

 known. With the faunas of horizons above the Oak Grove sands there is little 

 in common, though in the tropical waters of the Antilles about eight per cent, 

 of the species are believed to survive to the present day. Only about 2.6 per 

 cent, survive except in tropical waters. 



One of the most interesting features of the fauna is the assembly of land 

 shells, which are southern immigrants and have left no survivors on the 

 American continent at the present day, though representative species occur to 

 the southward. 



LIST OF TAMPA SILEX BED FOSSILS. 

 Those unmarked are from the outcrops at Ballast Point, Tampa Bay, and the shore 

 of the peninsula of which Ballast Point is the extremity. Those marked C are from the 

 rock, presumably of the same horizon, dredged up in deepening the ship channel near 

 Ballast Point. Those marked T are from a locality fifteen miles south of Tallahassee on 

 the railway to St. Mark's in Wakulla County, near Wakulla, collected by Mr. T. Way- 

 land Vaughan. * also recent. 



LAND AND FRESH-WATER PULMONATES 



Bulimulus (Hyperaulax) floridanus Con- Bulimulus (Hyperaulax) americanus 



rad. Heilprin. 



Bulimulus (Hyperaulax) Heilprinianus Bulimulus americanus var. partulinus Dall. 



Dall. Bulimulus americanus var. laxus Dall. 



