Vol. XXVII."! Hardy, Notes on Ramsden's Cave. 7 



1910 J ' ' 



specimen could be seen, and the first conclusion I came to was 

 that the diatom had been carried into the* cave from some sunlit 

 body of water. I have not yet had an opportunity of investigat- 

 ing the alternative theories, viz. — (i) That there are living diatoms 

 in the pool, and that the specimens examined died after collection 

 and during the many months that elapsed before examination ;^ 

 and (2) that H, amphioxys, regarded by West as " the only 

 fresh-water species of the genus," but by Van Heurck as inhabit- 

 ing " fresh and brackish water in England and Ireland," may be 

 or may have been a marine species also,! and has reached the 

 cave-pool through its fossil remains having been released from the 

 surrounding rock. With this in view, I crushed some of the cave- 

 rock, but found no trace of diatoms. Further investigation may 

 clear up this point. 



Though numerous gypsum crystals on the walls indicated the 

 presence of fossil shells, I saw no sign of stratified beds of these 

 latter, but, with a poor torch, and mud on the walls, much may 

 have remained obscured. 



This high-level cave appears to have been formed as follows : — 

 There was first the undermining of the cliffs until the indent was 

 cut, and afterwards until a tunnel of about 200 feet was bored. 

 The great thickness of the superincumbent rock had resisted all 

 attempts at blowhole formation, but the effect of intermittent air 

 compression and wave shock in the tunnel was the loosening of 

 the rock immediately above, and this fell, sliding down between 

 the joint planes at 70 deg. of dip, and thus more than filling the 

 old tunnel, and, with the falling of the cliff face continuing, a 

 talus was formed protecting the lower part of the scarp, and 

 further weathering of the upper cliff added to this, and also 

 formed an internal talus, which slopes to the edge of the pool, 

 about 45 feet above sea level. The ridge formed by the upper 

 part of this accumulation almost completely closed the cave. At 

 first the water which entered got away rapidly by soakage, which 

 was soon retarded by the sediment filling the crevices with fine 

 mud. 



To those who desire to inspect this novelty I would advise 

 the inclusion of this with many other bye-excursions of interest 

 to be made from Apollo Bay, whence, taking advantage of newly 

 made cuttings in the hillside and the rock platform at low tide, 

 vehicular traffic, in the hands of a good driver, is practicable as 

 far as Sugar-loaf Hill, a suitable camping place, or to Mr. 

 Ramsden's house, where refreshnents, information, an<1 necessary 

 assistance may, by pre-arrangement, be obtained. Mr. Ramsden's 

 address is Skene's Creek. 



* A fiesh but smaller sample examined on arrival contained no diatoms, 

 though collected in the same way a year later. 



+ The species was scarce in the Van Yean Reservoir as a littoral alga in 

 December, 1905, as recorded by G. S. West. 



