100 MR. G. NEVILL ON THK [Feb. 17, 



tiana, but also in close proximity to most of the deposits ^ to ^ ; 

 but though fragments were very numerous all round, I could never 

 succeed in finding a single bit even undoubtedly associated with 

 these subfossils, which I here attribute to the " phases eozoi'que et 

 dizoique." 



2. Intermediate Period. 



Under this heading I comprise a certain number of species, cha- 

 racterized by the remarkable gigantic Helix paretiaiia, Issel, which 

 can be found, here and there, all along tbis part of the Kiviern, and 

 which most certainly, in my opinion, are of a more recent age than 

 the preceding ; most of them are closely allied forms to those still 

 found living in this submaritime zone. 



This zone of H. paretiana requires still further investigation, a 

 matter of considerable difficulty, as the mollusks do not appear as yet 

 to have been found actually in situ. Those I found were evidently iso- 

 lated washed-down specimens, mostly in bad condition, and incrusted 

 in the rock, from which it was often impossible to extract them. At 

 Cape Mortela, indeed, where they occur at a considerable depth 

 (perhaps some 40 or 50 feet below the surface), they are preserved 

 in better condition in the comparatively soft " Couche Marneuse." 

 Immediately above them here, in perfectly similar deposit, occurring 

 at a depth of, approximately, 10 feet or so, can be found in profu- 

 sion present-existing species, such as H. aspersa, H. vermiculata, H. 

 cespitum, Pupa muttidentata, Rumina decollatu, Cyclostoma elegans, 

 &c. The most characteristic forms I found immediately associated 

 with H. paretiana were Hyalina olivetorum and H. herculcea, a 

 variety of Rumina decollata much stouter and larger than the exist- 

 ing form, one or two species of the group Xerophila, allied to, but 

 quite distinct from, X. cespitum, which is found in profusion imme- 

 diately above, and two species of the grotip Tachea, &c. I think 

 this " Couche Marneuse " at Cape Martela clearly proves H. pare- 

 tiana and its associated mollusks to have immediately preceded the 

 present fauna, without any very marked break, either of change in 

 the climate or otherwise. 



3. Present Period. 



This I should divide into two well-marked zones, having but very 

 few species in common, Pupa quinquedentata being a marked excep- 

 tion — Submaritime and Subalpiue Zones. 



A. Submaritime Zone. — Especially characterized by species of 

 Xerophila, Macularia vermiculata, Leucochroa candidissima, Ru- 

 mina decollata, Ferussacia and CcBcilianella spp., Clausilia solida, &c. 

 It is, perhaps, worthy of notice that I found the common species of 

 Pomaiia, Xerophila, &c., almost without exception, of larger dimen- 

 sions than those recorded as "major" in Pfeiffer's Monogr. 



B. Subalpine Zone. — On account of my bad health I was unable 

 to explore the higher elevations, where many interesting forms doubt- 

 less still remain to be discovered. My friend Coombe Williams was 

 good enough to make several expeditions to the summits of the neigh- 



