402 D. Bell — The Great Ice Age and Submergence. 



intermuscular bones. The fins consist of long slender rays, with 

 distant articulations, and apparently never forked more than once 

 at the distal end. Each is fringed by three or four very long and. 

 slender fulcra, which are conspicuous by their enamelled surface. 

 The slender pectoral arch of one side is displaced backwards, 

 and the imperfect pectoral fins, with the characteristic fulcra, are 

 shown. One of the hour-glass-shaped pelvic fin-supports is ex- 

 hibited, and some of the delicate pelvic fin-raj^s adpressed to the 

 ti'unk reach as far as the origin of the anal fin. The dorsal fin is 

 short-based, arising near the middle of the back and opposite to the 

 pelvic pair. Nine supports, of which the anterior ones are stouter 

 than the rest and somewhat winged, can be counted in front of the 

 disturbing vein of calcite ; and the long dorsal rays are pressed 

 down upon the back so that their distal ends appear behind this 

 vein. The anal fin arises behind the posterior end of the dorsal, 

 and comprises about eight rays, which when adpressed reach nearly 

 to the base of the caudal fin. The latter fin is imperfect and dis- 

 torted, and it is impossible to determine whether or not it was 

 forked. Delicate scales may have covered the trunk, but there is 

 no clear evidence of them. Eobust ganoid ridge-scales, however, 

 are observable on both borders in the hinder half of the caudal 

 region ; and those of the dorsal border are shown to be remarkably 

 acuminate, the apex of each scale being especially produced into 

 a long point at the base of the upper caudal lobe. 



In short, so far as can be determined from this unique specimen, 

 Ceramurus does not exhibit any special feature of resemblance to 

 Mpgalurus. The fins bear large fulcra, while those of Megaliirus 

 are non-fulcrated ; the form of the caudal fin is unknown; the 

 dorsal fin is remarkably short ; the vertebral centra are merely 

 spaced rings. On the whole, the fish appears to the present writer 

 to be most closely related to PhoUdophorus, and it will probably 

 prove to have a forked tail. The axial skeleton of the trunk, the 

 fins, and the caudal ridge-scales are especially suggestive of PhoU- 

 dophorus ; but Ceramurus diffei's in the large size and fewness of 

 the slender fin-fulcra, in the unusual development and serried 

 arrangement of the dorsal ridge-scales of the tail, and in the 

 apparent absence of scales on the flanks. The fish may, therefore, 

 be provisionally assigned to the Pholidophoridfe, under the generic 

 and specific name which Egerton proposed for it. 



IV. — Notes on "The Great Ice Age" in Eelation to the 



Question of Submergence. 



By DuGALD Bell, F.G.S. 



{Continued from p. 355.) 



V. Changes of Level in Eelation to Climate. 



LEAVING those local matters, there is a point of some general 

 interest, suggested by several passages of Dr. Geikie's work, 

 which we should like briefly to notice before laying it aside. It 

 is in regard to those repeated depressions and re-elevations of the 



