472 Systematic Paleontology 



beyond the penultima; anterior and posterior margins of the wing con- 

 vex, the anterior more strongly so than the posterior ; outer margin sub- 

 vertical or feebly oblique. 



The shell of A. rostrata (Gabb) is best characterized by the sub- 

 quadrate wing and the numerous, rather narrow, obtuse and feebly 

 arcuate axial riblets. It is not only smaller than the closely related 

 A. pennata (Morton), but it differs further in the more rapidly enlarging 

 whorls. 



Anchura rostrata is the most conspicuous gastropod in the Matawan 

 along the Chesapeake and Delaware Canal. The material is in a very poor 

 state of preservation, the forms occurring as casts, most commonly in the 

 iron nodules. The casts are small for the genus, not more than 20 mm. 

 high, as a rule, and are characterized by the angular outline and the 

 numerous axial plications. 



Occurrence.— Matawan Formation. Post 105, Summit Bridge, 

 ? one-eighth of a mile west of Summit Bridge, Chesapeake and Delaware 

 Canal, Delaware. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, New Jersey Geological Survey, U. S. National Museum. 



Outside Distribution. — Matawan Formation. Merchantville clay marl, 

 Woodbury clay, Wenonah sand, New Jersey. Ripley Formation. Exogyra 

 costata zone, Tippah County, Mississippi. 



Anchura pennata (Morton) Conrad 



Rostellaria pennata Morton, 1834, Syn. Org. Rem. Cret. Group, U. S., p. 48, 



pi. xix, fig. 9 (very poor). 

 Rostellaria? pennata Meek, 1864, Check List Inv. Fossils, N. A., Cret. and 



Jur., p. 20. 

 Anchura pennata Conrad, 1868, Cook's Geol. of New Jersey, p. 729. 

 f Rostellaria compacta Whitfield, 1892, Mon. U. S. Geol. Survey, vol xviii, 



p. 108, pi. xiii, figs. 18-21. 

 ? Rostellaria spirata Whitfield, 1892, Ibidem, p. 109, pi. xiii, figs. 16, 17. 

 Anchura pennata Whitfield, 1892, Ibidem, p. 115, pi. xiv, figs. ? 7, ? 8. 

 '/ Anchura (Drepanochilus) compressa Whitfield, 1892, Ibidem, p. 117, pi. 



xiii, figs. 22-25. 

 Anchura pennata Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 22. 

 ? Rostellaria compacta Johnson, 1905, Ibidem, p. 23. 



