AND OTHER ENGLISH NUMMULITES. 



145 



E. Edwards ; and Emsworth, with Turhinolia, E. Edwards. Of 

 these some, if not all, may have been wrongly localized (see above, 

 page 136). Eurther, from Bramshaw, Brook, and Highcliff ; the last 

 is thickish and associated with N. variolarius ; all from the late 

 Mr. Ered. Edwards's Collection. Some rare, dredged off Guernsey, 

 as noted in the Ann. & Mag. N. H. April 1876, p. 283. We have 

 received from the Bev. 0. Eisher and Mr. Keeping some from Hunting 

 Bridge and from Highcliff, also some in a glauconitic clay from 

 Whitecliff Bay, found by Mr. Keeping in a zone just below " no. 

 17" of Mr. Prestwich's Section*, and 13 inches thick. This is 

 regarded as equal to a part of " no. 29," Alum Bay. The specimens 

 are both large and small, compressed, and not pyritous. I may 

 mention that not only did Prof. Prestwich give me characteristic 

 specimens of the Prestivichianus and variolarius from their several 

 beds in or about 1852, but I took a note of the occurrence of 

 these and other "Nummulites as then preserved in his Collection. 



II. Nummulites vaeiolarius (Lamarck). PI. XI. figs. 10-14. 



1804. Lenticulites variolaria, Lamarck, Annales du Museum, vol. 

 v. p. 187, no. 2. 



1826. Numrnularia variolaria, Sowerby, Min. Conch, vol. vi. 

 p. 76, pi. 538. figs. 3 (nos. 12-17). 



1854. Nummulites variolaria, D'Archiac et Haime, Monogr. 

 Numm. p. 146, pi. 9. fig. 13. 



Nummulina et Nummulites variolaria, auctorum f . 



Small, smooth, lenticular, with a rather sharp edge ; the alar 

 extensions are numerous (18-20 visible), distinct, long-triangular, 

 nearly all reaching the umbo on the convex faces of the shell ; the 

 median chambers are usually about as high as long ; central 

 chamber rather large ; the whorls four, regular, increasing slowly. 

 Occasionally the septal lines become thickened and raised, chiefly by 

 a lessening of the shell-matter along the alar intervals; and a 

 radiately-ribbed appearance is thus given to the shell. A swollen 

 condition of the alar extensions also, in some cases, gives a similar 

 appearance. See ' Min. Conch.' pi. 538. fig. 3 (no. 16) : and 

 Dixon's ' Geol. Sussex,' pi. 9. fig. 7. 



The alar parts of the chambers, in passing to the umbo, often 

 vary from their usual straight line to a gently curved, and even 

 falcate form, thus passing from the " radiate " to the " sinuo- 

 radiate" type of Nummulite. They rarely interfere one with another. 

 The umbo is always conspicuous, and sometimes flattened. The alar 

 septa are often strong, but not so thick as in the young N.planulatus. 

 The latter, moreover, soon loses its convexity between the umbo 

 and margin ; in its young state it is " radiate," and in the adult 

 condition fully " sinuo-radiate." See Ann. & Mag. N. H. ser. 3, 

 vol. viii. pp. 233, 234. 



* See above, page 138. " No. 16 " contains N. variolarius as a characteristic 

 fossil. 



t Some remarks by Dr. Ph. De la Harpe on this species are given in the 

 'Bull. Soc. Geol. Prance,' ser. 3, vol. v. pp. 826, 827 (1879). 



