289] B. Wade 91 



ern Mississippi. The genus is represented by three species at 

 Coon Creek. Mataxa is a form regarded by me as a new 

 genus and is referred to the Cancellariidae. A species of 

 Mataxa has been described from South India by Stoliczka 1T 

 and asigned to the genus Narona of the Cancellariidae. A 

 study of Stoliczka's description and figures together with 

 perfect specimens from Coon Creek shows that these species 

 belong to the same genus which is evidently not Narona, so 

 it seems advisable to assign these two forms to Mataxa as a 

 new genus in the Cancellariidae. The Turritidae is another 

 family which is represented in the Cretaceous by several 

 forms and is not found in earlier strata. There are two gen- 

 era of this family at Coon Creek, Turris, and Surcula. The 

 latter is especially varied, and includes probably six species. 

 The Volutidae is the most prolific and interesting family 

 of the Coon Creek collection. It contains six genera and 

 sixteen species, nearly all of which are represented by abun- 

 dant, well characterized and perfectly preserved shells. The 

 remarkable efflorescence of the Volutes in the Upper Creta- 

 ceous has been discussed by Dall who mongraphed the Volu- 

 tidae in 1890 18 and in 1907. 19 The Coon Creek Volutes 

 include the genera Volutomorpha, Volutoderma, Ptychosyca, 

 Liopeplum, two new genera, Drilluta and Tectapl^ca and two 

 species of a form whose generic relations have not been fully 

 determined. The genus Ptychosyca was named and described 

 by Gabb in 1876. 20 Dall did not consider this genus a 

 Volute in his monograph of this family, but two species re- 

 presented by well preserved material in the McNairy County 

 collection reveal new characters that indicate that this form 



17 Stoliczka, F., Geol. Surv. of India, Cret. Faunas of South India, 

 vol. ii, p. 166, pi. xiii, figs. 15, 16. 



18 Dall, 1890, Trans. Wagner Free Inst. Sci., Philadelphia, vol. iii, 

 pt. 1, p. 72. 



19 Dall, 1907, Smiths. Misc. Coll., vol. iv, pt. 1, pp. 1-23. 



20 Gabb, W. M., Proc. Acad. Nat. Sci., Philadelphia, 1876, p. 295, 

 pi. 17, figs. 2-4. 



