612 



SCIENCE 



[N. S. Vol. XLI. No. 1060 



SCIENTIFIC BOOKS 



A Monograph of the Molluscan Fauna of the 

 Orthaulax Pugnax Zone of the Oligocene of 

 Tampa, Florida. By William Healey Dall, 

 U. S. Nat. Mus., Bull. No. 90. Pp. sv, 173; 

 PI. 1-26. Jan. 21, 1915. 

 Collectors of curios and fossils alike have 

 long known of tlie beautifully preserved speci- 

 mens in the Tampa "silex beds" of Florida. 

 But their chief interest, as the author of this 

 monograph aptly remarks, " is not limited to 

 their esthetic beauty, nor their position as 

 characteristic of one horizon in the series il- 

 lustrating the evolution of life on the globe, 

 but is of extreme importance as furnishing a 

 key to the little-understood succession of the 

 Tertiary beds which fringe the islands of the 

 West Indies and the encircling continental 

 shores of Mexico, Central America and north- 

 ern South America. The Tertiary column of 

 the coastal plain of the Gulf states being 

 fairly well elucidated, the relative position of 

 the deposits to the south can be determined 

 if any one of them can be satisfactorily con- 

 nected with a given horizon in the North 

 American series. Such a connection is af- 

 forded by the fauna of the silex beds of 

 Tampa." 



This problem confronting the paleontolo- 

 gists of the New World is strictly analogous 

 to that presented Mesozoic and Cenozoic 

 workers in the Old, viz., correlating northern 

 temperate faunas with widely differing ones 

 of a more southern, tropical character. There, 

 much progress is being made of late in the 

 older Tertiaries by the use of organisms other 

 than molluscan, especially Foraminifera, and 

 a similar tendency will doubtless soon be 

 shown in this country. Yet there, such forms 

 as Velates Schmiedelianus have served well 

 as indices of horizons in both the southern and 

 northern provinces of Europe, and such char- 

 acteristic types aa Orthaulax pugnax are 

 equally serviceable here, from the Panama 

 Canal to Georgia. Incidentally we may note 

 the author's attempt to designate other hori- 

 zons by characteristic species, as, for example, 

 in the upper Oligocene : 



Zone of — 

 Scapharca dodona 

 Cardium oestum 

 Orbitolites floridanus 

 OrthaMlaa pugnax 



Former designation- 

 Alum Bluff beds 

 Chipola marl 

 Tampa limestone 

 Ortliaulaa bed 



It is certain that only by the study of such 

 faunal zones we may ever hope to be able to 

 correlate the widely scattered Tertiary deposits 

 of the West Indies and Central America. 



As regards the relations of the fauna of the 

 Orthaulax pugnax zone Dall says: 



Pour species go back as far as the Claiborne 

 sands, six are found in the Jackson Eocene, 

 and seven in the Vicksburg. Eight come up 

 from the Lepidocyclina zone, four have been 

 recognized in the scanty fauna known from 

 the Nummulitic zone, and one or two from 

 the very imperfectly explored Chattahoochee 

 fauna. Eight are known from the Tertiary 

 of Santo Domingo, several of which are very 

 characteristic of the zone. The two character- 

 istic species of Orthaulax occur in the lower 

 Oligocene of the Panama Canal Zone, and at 

 least one of them has been obtained in Santo 

 Domingo, Antigua, and Anguilla. 



" Above the Orthaulax zone we find 51 of its 

 species surviving in the Cardium cesium zone, 

 but only 14 reach the zone of Scapharca 

 dodona. 



" Fifteen occur in extra-Floridian Miocene 

 beds, but only three in the Floridian Miocene; 

 11 are found in the Pliocene of south Florida, 

 and five in the Florida Pleistocene, while 23 

 survive in the recent fauna." Of the 312 mol- 

 luscan species known from the Orthaulax pug- 

 nax zone, 90 are described in this monograph 

 as new, while about 120 are refigured from the 

 author's well-known Wagner Institute papers. 

 More than half the remaining species described 

 by various authors are discussed and re-figured. 



Of special interest in this generally marine 

 assemblage of species is the presence of 27 

 land and fresh-water forms, consisting, among 

 others, of Helix-lihe, Bulimoid, Pupoid and 

 Planorhis types. One new genus is described, 

 viz., Microcerion " about midway between 

 Cerion proper and the small Pupidse." 



No sympathetic regard for generic names 



