98 THE MOLLTJSCA OE THE CHALK ROCK. [Feb. 1 896. 



Fig. 12. Gerithium Smmdersi, sp. no v. Cuckhamsley. Montagu Smith Col- 

 lection. Nat. size. 12 a. Whorl, X 1^. Drawn from a wax mould. 

 13, 14. Lampusia (?), sp. Cuckhamsley. Montagu Smith Collection. 

 13. Drawn from a wax mould, x 1$. 14. Internal mould, nat. size. 



15. Avellana, sp. (cf. Humboldti. Miiller). Cuckhamsley. Montagu 



Smith Collection. Drawn from a wax mould. X If. 



16, 17. Dentalium turoniense, sp. no v. Cuckhamsley. Montagu Smith 



Collection. 16. Internal mould, nat. size. 17. Ornamentation, X 4. 



Discussion. 



Dr. W. F. Hume pointed out, in connexion with the zonal name 

 applied by Mr. Woods, that the horizon in question has already 

 received the name of the Holaster planus-zone, that fossil being 

 fairly abundant in England. The Author holds that the fauna is 

 shallow-water in character, but Trochus, Natica, and Dentalium 

 occur not uncommonly at over 1000 fathoms, while, with the ex- 

 ception of Gerithium and Emarginulina (the range of Orepidula 

 and Cinulia had not been studied by the speaker), the others have all 

 been found to range over 500 fathoms. Finally, the interesting com- 

 parison with the Lower Chalk fauna is one of the highest importance, 

 and will prove helpful in determining the physical conditions of 

 this disturbed period. 



Mr. R. S. Herries was very glad that the Author was working 

 out so interesting a fauna as that of the Chalk Eock. He wished, 

 however, to protest against the invention of a new name for a 

 horizon for which a very good one was already in existence ; the 

 more so^ as, if the proposed new name was persisted in, from what 

 the previous speaker had said, there would be three names to signify 

 the same bed. 



_ Prof. Hull, on the other hand, thought it desirable that a less 

 'insular' name should be substituted for that of < Chalk Rock,' 

 originally adopted by Mr. Whitaker. Now that it had been shown 

 by the Author of the paper and others, such as M. C. Barrois, that 

 this band was so rich in organic forms, and had so wide a range, 

 not only in the British Isles but in Europe, he considered it desirable 

 that some name of wider significance should be accepted, and one 

 which would be recognized on the Continent ; and as the name 

 ' Zone of Holaster planus ' had been suggested by M. Barrois he 

 hoped that it would be generally adopted by geologists. 



Prof. H. G. Seeley and Mr. J. E. Marr also spoke. 



