14 STUDIES IN GEOLOGY, No. 3 



would expect. The recent Peruvian littoral fauna contains 

 four species of Turritella. Maury 9 lists but three species 

 out of the 451 discussed by her from Santo Domingo; the 

 rich Bowden fauna contains but two species; the Chipola 

 fauna contains six species and varieties ; 10 the Oak Grove 

 two j 11 the Tampa silex beds five species and varieties. 12 The 

 only American tropical fauna which approaches the Zorritos 

 in mere number of Turritellas is the extremely rich Cal- 

 loosahatchie assemblage, .which contains 12 species and 

 varieties. It is worthy of note that of the twelve, seven 

 are peculiar to the deeper water faunule of the Calloosa- 

 hatchie River locality, and all occur there; two more are 

 peculiar to that locality and the Shell Creek, which offers a 

 facies shallower, though probably still deep, and thus at 

 least cooler water. It is thus probable that all of these 

 species are deeper water forms. The other Pliocene faunas 

 are poor in Turritellas; the Waccamaw contains but one. 

 The Duplin Miocene, a warm-water fauna, contains about 

 nine or ten species and varieties, all of which are very much 

 alike. 



In face of comparative data such as these the occurrence 

 of so varied and extensive a development of the genus in a 

 fauna, the data on which are by no means complete, is at 

 least interesting. Analysis of such scattered data on the 

 habitat of the genus as are available shows that Turritella 

 seems to prefer comparatively deep water ; however, nothing 

 definite can be said on that question, since published data 

 conflict to large extent, and there is thus no certainty. It is 

 difficult, in the absence of even a little reliable ecologic 

 information, to say whether or not the abundance of the 

 Turritellas in the Zorritos fauna means a deep-water origin 

 of the beds enclosing them. The evidence of the lithology, 



'Bull. Amer. Pal., vol. 5, No. 29, pp. 129-130, 1917. 



"Ball, W. H., Trans. Wag. Inst, vol. 3, pt. 6, p. 1577, 1903. 



11 Ibid., p. 1590. 



12 Ibid., p. 1567. 



