NASSA GRANULATA. 



1 1 



Specific Cliaracfers. — See Mon. Crag Moll., pt. i, p. 30. 



Dimensions. — L. 15 — 20 ram. B. 8 — 10 mm. 



Distrihiitloii. — Not known living. 



Fossil : Waltonian Crag (abundant) : Walton-on-Naze, Beaumont, 

 Little Oakley. Newbournian : Bentley, Waldringfieltl, Newbourn, Sutton. 

 Butleyan : Butley, Bawdsey. Isle of Man. Slains, Aberdeenshire. Scaldisien : 

 Belgium. 



Remarks. — As just stated, it seems to me that in 1843 Nyst reversed the names 

 of this species and of the N. consocioto of the English Crag. His specimen of 

 1881 [op. cif., fig. 5) corresponds more nearly with Sowerby's species N. eler/ans. 



The latter form has not been reported from the Coralline Crag, but is one of 

 the most characteristic and common forms of Waltonian deposits. With the var. 

 intermedia I have more than 200 specimens of it from Oakley in my collection. 



Mr. A. Bell has sent me an imperfect but recognisable example from the Isle of 

 Man which has been found recently by the Rev. S. N. Harrison. 



Nassa granulata (J. Sowerby). Plate V, figs. 1—4; Plate XIII, fig. ^20. 



1818. Buccimim gramdatum, J. Sowerby, Min. Couch., vol. ii, p. 18, tab. ex, fit^-. 4. 



18i3. Buccimim gramdatum (!), Nyst, Coq. foss. Terr. Tert. Belg., p. 575, pi. xliii, fig. 11. 



1848. ^assa gramtlata, S. V. Wood, Mou. Crag Moll, pt. i, p. 29, tab. iii, fig. 3. 



1870. Nassa granulata, S. V. Wood, Jan., and F. W. Harnier, Eep. Brit. Assoc. (Liverpool), Trans. 



Sect., p. 91. 



1881. Nassa gramilata, Nyst, Couch. Terr. Tert. Belg., p. 24, pi. ii, fig. 6. 



1888. Nassa granulata, A. Bell, Eep. Brit. Assoc. (Bath), p. 139. 



1892. Nassa granulata. Van den Broeck, Bull. Soc. Belg. Grcol., vol. vi (Momoires), ^. 121. 



1912. Nassa granulata, Tesch, Med. v. d. Rijks. v. Delfstoft'en, pt. iv, p. 8U. 



Specific Characters. — See Mon. Crag Moll., pt. i, p. 29. 



Dimensions. — L. 10—15 mm. B. 5 — 6 mm. 



Distritjiition. — Recent : Japan. 



Fossil : Coralline Crag. AYaltonian ; Xewbournian ; Butleyan ; 

 Icenian. Isle of Man. Pleistocene: Middle Glacial sands, Billockby; Ballybrack 

 Bay, Killiney. Scaldisien : Belgium, Holland. 



Remarhs. — -Of this well-known and abundant Red Crag species, specimens of 

 which may be collected almost by the thousand in the Waltonian deposits, four well- 

 marked varieties, here figured, occur at Little Oakley, the typical form (fig. 1) 

 being rather. the most abundant. Fig. 3, however, Avhich I distinguish as var. 

 gracilis, is exceedingly common at that place, and may be found in our public collec- 

 tions from other horizons in the Crag. It is a smaller and more delicate shell than 

 the type ; the sculpture is finer, both the longitudinal and transverse ridges 

 being more numerous and less pronounced, and the intersecting points generally 

 less nodulous, giving the shell a finely reticulate rather than a strongly granulate 



