FAUNA OF OETHAULAX PUGNAX ZONE. 7 



our present Imowledge goes) , 13 identical with species found at Vicks- 

 burg, and 15 (including in this case foraminifera) are inherited from 

 the Peninsular limestone, which was followed by the Ocala with con- 

 tinuous sedimentation but with the changes of fauna above indicated. 



The Ocala or Nummulitic limestone of Heilprin was first dis- 

 covered by Mr. Joseph Willcox and discriminated from the Penin- 

 sular limestone, of which it seems to form a culminating phase, by 

 Prof. Angelo Heilprin. The stratum, though thin, is, according to 

 Doctor Vaughan's observations, quite widely spread, and is every- 

 wdiere characterized bj^ a specially abundant content of foraminifera, 

 particularly the Nummulites and Miliolites. The former are not 

 absolutely confined to the Ocala phase, but elsewhere are relatively 

 rare, indicating perhaps the slowness Avith which the Nunnnulitic 

 fauna of southern Europe and northern Africa was able to make 

 its way westward, following the Orbitoides or Lepidocyclinas and 

 Orbitolites. The last mentioned have been able to persist to the 

 present time, having been dredged by the peck in the Gulf of Mexico 

 by the expeditions of the United States Bureau of Fisheries. 



The Chattahoochee group, of which the typical locality is at New 

 Chattahoochee Landing near the railway bridge over the river of the 

 same name, was named by Langdon in 1887, who, by misidentifica- 

 tion of fossils, was led to describe it as of Miocene age. The fossils 

 are not numerous and as a rule are poorly preserved. 



The Orthaulax bed has been sufficiently described above, as has 

 the overlying limestone named in 1892 by the writer, the Tampa lime- 

 stone, which though apparently conformable with the former has 

 so far failed to yield to collectors some of the most characteristic 

 fossils, such as Ortliaidax and Yillorita^ and contains numerous 

 others, especially Cerites, which have not yet been found in the 

 Orthaulax bed. 



The '\\'liite Beach limestone of Little Sarasota Bay^ has a fauna 

 in many respects similar to that of the Orthaulax bed, and yet the 

 identifiable species are not sufficiently numerous to decide whether 

 it may be regarded as its exact equivalent or not. The question is 

 complicated by the presence in the White Beach fauna of several 

 large and conspicuous species not known from the Orthaulax bed, 

 especially the Conus demiurgus, a large Cypraea, a Mytilus, and 

 others. 



The Tampa limestone (which includes Heilprin's '■'■ C erithium 

 rock") lies immediately over the Orthaulax bed at Ballast Point, 

 but owing to its being at or nearly at the surface has been recog- 

 nized over a wider area.- It is largely free from silex, the fossils 

 are mostly represented by external molds, and it was referred with 

 the Orthaulax bed to the Middle Miocene by Heilprin. The Jack- 

 ie Trans. Wagner Inst., vol. 3, p. 1568. 

 2 Idem., p. 1570. 



