274 SUPERFICIAL DEPOSITS 



floor. Adjacent to this deposit are some shallow, dried-up tarns containing abund- 

 ance of diatoms and lacustrine algse. 



4. Cape Bavne. The fourth raised marine mud deposit is about half-way 

 between Cape Royds and Cape Barne, distant about 15 chains from the small bay 

 near where the position of the green and blue flags are shown on the geological map. 

 This deposit was discovered by one of us (R. E. P.), and has proved specially rich in 

 remains of ostracods and foraminifera, as well as in several types of mollusca. The 

 ostracods and foraminifera are described in detail by Mr. Frederick Chapman, and 

 the molluscan remains by Mr. C. Hedley, in Vol. II. of this Memoir. 



Mr. Chapman remarks tliat, iu addition to the forms mentioned, Polyzoa (Callaria) 

 and other genera, some echmoid test fragments and spines, and numerous siliceous 

 sponge spicules (TetractinelUa) are present. He states that the valves of the 

 ostracods were exceptionally well preserved, and must have been floated together 

 and gathered up by very gentle sedimentation. He makes the following remark, 

 specially important from the raised beach standpoint: "Judging from the general 

 foraminiferal fauna of the Mount Erebus raised beach deposit they were formed 

 iu moderately deep water like the preceding series from south-east of Mount 

 Larsen, viz. at or near 100 fathoms. The presence of many delicate-shelled ostracoda 

 in the material from locality two indicates to my mind a decided clarity of conditions, 

 as distinguished from the more salty or terrigenous deposit of tlie sample from the 

 south-east of Mount Larsen." 



If the view of Mr. Chapman be adopted, this raised beach of Cape Barne indicates 

 an elevation of considerably more than that represented by that of the altitude at 

 which they occur at present above sea-level. In fact they may indicate an elevation 

 of as much as 760 feet.* 



5. Possible Raised Beaches near Hut Point. As already stated, Ferrar has 

 recorded the occurrence of Balanus shells attached to Ice-scratched stones of moraine 

 cones between White Island and Black Island. These moraines are also probably 

 to be looked upon as of glacial upthrust origin. Like the raised beaches of Back- 

 stairs Passage, they appear to rest on a foundation of ice. This Is described by 

 Ferrar as floating ice, and it may be so ; but if floating, It is hard to understand how 

 the sea could have extended over the top of it so as to account for the present 

 position of the Balanus shells, unless the latter are of the nature of push moraine 

 upthrust from some depth. The level of the raised beach between White and Black 

 Island is not given by Ferrar, but, judging from the height of the Barrier cliflts when 

 broken away to the farthest point south in the direction of White and Black Island, 

 it cannot be less than 50 feet. At Hut Point the discovery was made of several 

 balls of white, finely-felted material, which proved to be entbely built up of delicate 

 spicules of siliceous sponges. These were discovered by one of us (R. E. P.) on a 



* This is of course on the assumption that the Cape Barne deposit is a genuine raised beach rather 

 than an upthrust part of the adjacent floor of McMurdo Sound. 



