86 Correspondence — R. M. Deeley. 



mingled with bits of felsite and other material, were deposited as the 

 peculiar limestone breccias. This view regarding their formation is 

 held to afford an adequate explanation of the patchy development of 

 these rocks. 



The intrusive rocks are of considerable interest. They are, in the 

 main, felsites with large quartz-crystals, and not infrequently contain 

 augite. Some of them are certainly intrusive in the coarse Bala (?) 

 conglomerate. A number of small but interesting intrusions of olivine 

 dolerite, hornblende lamprophyre, and fine-grained oligoclase bearing 

 rocks are scattered throughout the district. 



The appendix embodies a critical review of the fauna of the 

 Llandeilo Beds of the district, and a description of several new species 

 of brachiopods and trilobites. 



COI^I?-ES:POITIDE3SrCE. 



POST - GLACIAL CONDITIONS OF THE BRITISH ISLES, AND 

 PRESENT GLACIAL PHENOMENA OBSERVED IN ANTARCTIC 

 LANDS. 



Sir, — Ever since the publication by Captain H. F. Scott of The 

 Voyage of the Discovery, in which he gives his impressions of the 

 Great Barrier discovered by Sir James Ross, we have been asked to 

 suspend our judgment concerning its actual physical features. It is 

 not quite clear what is now the uncertain feature in the minds of 

 those who ask us to delay ; but it would appear that this counsel 

 results from a fear that if the conditions of the barrier are as stated 

 it cannot be maintained that a similar ice-sheet did not once fill the 

 area now occupied by the J^orth Sea during the Ice Age. 



To those who consider that the glacial phenomena of the British 

 Isles prove that an ice-sheet did move from Scandinavia over the 

 ISTorth Sea area and invade the east of England, the facts concerning 

 the Great Barrier are of the highest importance. 



Although there is abundant matter for further investigation in the 

 Antarctic area, the facts put on record by Sir James Ross and Captain 

 Scott are sufficient, I think, to warrant my calling attention to their 

 great interest to the glacial geologist. 



From about 71° S. lat. to about 83° S. lat. and 167° E. long. 

 a range of snow- and ice-covered mountains runs in the direction of 

 the Soiith Pole. Some of the summits exceed 15,000 feet in height, 

 and the range forms, for at least 800 miles, the eastern boundary of 

 South Victoria Land. It rises abruptly from the ice-covered sea. 

 About the centre of the known portion of this great mountain range 

 is the active volcanic cone of Mount Erebus. It is not, however, 

 actually a portion of the range, for it stands on an island close to 

 the shore. 



From Erebus stretches the Great Barrier in an easterly direction. 

 This ' wall of ice ', which faces the open sea, varies in height from 

 50 to 240 feet and extends as far as King Edward VII Land, a distance 

 of about 390 miles. The depth of the sea along its edge, according to- 



