'624: Reports and Proceedings — 



Lias of Lyme Regis. He now described some new specimens which add to our know- 

 ledge of their characters. An example of Platysiagum shows the position of the 

 dorsal fin, which is placed very far back, occupying a place opposite to the interval 

 between the ventral and anal fins, and the form of the trunk, which is of nearly 

 uniform depth from the occiput to the base of the dorsal fin. The structure of the 

 dorsal fin was described in detail. The new specimen of Falaospinax priscus shows 

 especially the position of the second dorsal spine, which is placed over the fiftieth 

 vertebra, the first being on the 16th, the fish thus most nearly approaching the existing 

 Cestracion, which it also resembles in its dentition. In other respects it seems to be 

 most nearly allied to Acanthias. 



Discussion. — Dr. Giinther observed that the families of sharks were most sharply 

 characterized, and especially that of the Spinacidse was a very natural group. He 

 did not in the instance cited doubt the absence of a separate anal fin, which was one 

 of the characteristics of the Spinacidse. 



He drew attention to the fact that the spined-sharks showed several singular pecu- 

 liarities with regard to their geographical distribution. Some belonged to the deep 

 sea. and were found at a depth of 800 fathoms, while others were even more truly 

 pelagic forms, and never approached the shore. Some were found both in the 

 northern and southern hemispheres so similar that specimens from the British seas 

 and from the Straits of Magellan and Australia could not be distinguished. This 

 geographical distribution was of great importance in considering the palseontological 

 aspect of such a case. 



4. " On a New Genus of Silurian Asteriadse." By Thos. Wright, M.D., P.E.S.E., 

 F.G.S. 



The specimen described showed the outline of a small Starfish, with a large disk 

 and short rays, in a slab of Wenlock Limestone from Dudley. The outline of the ten 

 rays was described as marked out by the border of small triangular spines, the other 

 plates of the disk and rays being absent. Each ray was terminated by a stemlike 

 multiarticulate process as long as the ray, from towards the extremity of which spring 

 slender lateral processes, giving it a tufted appearance. This Starfish, which is in the 

 collection of Dr. Grindrod, is named by the author Trichotaster plmmforinis. 



Discussion. — Mr. H. Woodward was somewhat doubtful as to the afiinities of the 

 specimen, the preservation of which appeared to him hardly sufficient for its specific 

 determination, though of all men Dr. Wright was the best qualified for such a task. 

 (3).— May 28th, 1873.— Prof. Eamsay, F.E.S., Vice-President, in the Chair.— The 

 following communications were read: — I. "The Glaciation of the Northern part of 

 the Lake-district." By J. Clifton Ward, Esq., E.G.S. 



The author stated the leading questions to be settled by his investigation of the 

 northern part of the Lake-district as follows : — The fact of the glaciation of the 

 district being granted, (and of this he adduced abundant evidence,) the questions that 

 arose were whether the glaciating agent worked from north to south, whether it 

 came from within or from without the district, and finally, whether the agent was 

 floating ice, a system of local glaciers, or an unbroken ice-cap. As the result of his 

 investigation, he maintained that there is no evidence that a great ice-cap from the 

 north ever swept over this district. The ice-scratches trending along the principal 

 valleys, but sometimes crossing watersheds, indicate a great confluent glacier-sheet, 

 at one time almost covering a great part of the district, the movement of which was 

 determined by the principal water-shed of the Lake -district. In the part of the 

 Lake-district under consideration the ice, during its increase, carried forward, from 

 eouth to north, a great quantity of rocky material. There are no signs in the district 

 of the occurrence of mild periods during the epoch of primary glaciation, but the 

 author thought that the climate had probably become moderate before the great sub- 

 mergence of the land commenced. The author noticed the effect of the submergence 

 upon the results of previous glacial action, and maintained that when the land had 

 Bunk 800 or 900 feet there was a recurrence of cold, and boulders were transported by 

 floating ice. Until the submergence reached 1500 feet there was no direct commu- 

 nication between the northern and southern halves of the Lake-district except by the 

 Straits of Dunmail Raise. Prom the directions which would be taken by the cur- 

 rents m the sea at this period, it would appear that boulders may then have been 

 transported by floating ice in some of the same directions as they had previously been 

 carried by glacier-ice. The extreme of submergence appeared to have been about 

 2000 feet. The author further maintained that on the re-elevation of the district there 

 was a second land-glaciation, afi'ecting the higher valleys and clearing them of 

 marine drift. 



DrscussiON. — Mr. Campbell expressed his general agreement with the views of 

 the author, though he was not acquainted with the particular district described. The 

 only question was, whether tiie valleys had been filled to such an extent by water 

 or by ice. He was rather inclined to consider the phenomena quite as much in 

 accordance with a general ioe-cap as with a submergence such as that suggested. 



