422 Geological Society. 
PROCEEDINGS OF LEARNED SOCIETIES. 
GEOLOGICAL SOCIETY. 
November 7, 1883.—J. W. Hulke, Esq., F.R.S., 
President, in the Chair. 
The folowing communications were read :— 
1. ‘ Notes on Brocchi’s Collection of Subapennine Shells.” By 
J. Gwyn Jeffreys, Esq., LL.D., F.R.S., F.G.S. 
In this paper the author gave the results of an examination of 
the collection of fossil shells from the Subapennine Pliocene described 
by Brocchi in his ‘Conchiologia fossile Subapennina,’ and now pre- 
served in the Museo Civico at Milan. He stated that the collection 
appeared to have been more or less tampered with, several species 
are unrepreseuted, and in other cases the specimens on the tablets 
with Brocchi’s labels have evidently been subsequently and erro- 
neously placed in their present situation. There are, however, 
many undoubted types. The author cited 55 of Brocchi’s species, 
upon most of which the collection furnished more or less interesting 
information. In conclusion he remarked upon the importance of 
identifying Brocchi’s species with forms still living in the neigh- 
bouring seas, and also upon the difficulty of distinguishing between 
the Upper, Middle, and Lower Pliocene in Italy. From his exami- 
nation of Italian Pliocene shells he concluded that the deposits con- 
taining them were for the most part formed in comparatively shallow 
water, probably not more than 50 fathoms in depth, a remark which 
also applies to the Italian Miocene; and that in the case of species 
still existing no difference can be recognized between Pliocene and 
recent specimens. 
2. “British Cretaceous Nuculide.” By John Starkie Gardner, 
Esq., F.G.S. 
The author commenced by discussing the question whether the 
Nuculidee should be separated as a family from the Arcide, and 
stated that species of Leda and Nucula exist and sometimes abound 
in the marine Cretaceous deposits, with the exception of the White 
and the Red Chalk, from which, however, he thought that the 
shells may have been dissolved out. He also referred to the pro- 
bable derivation of the’species from preexisting forms, and discussed 
the question of how far the relationships thus established could be 
expressed in the nomenclature of the species, his researches upon 
the Nuculidze leading him in some cases to suggest a trinomial 
nomenclature. The probable lines of descent of the shells described 
in the present paper were also discussed at some length. 
In the genus Nucula the author distinguished certain groups 
typified by particular species, his trinomial system of nomenclature 
consisting in the intercalation of the names of the latter between 
the generic name and the definitive specific name of the individual 
