^wii itji 



r-^:f -.r^-t^-jir^sl^i^ 



GEOLOGY. 



125 



have abandoned this view in favour of an aohan origin. The equal and 

 minute size and the complete rounding of the particles; the abundance ot 

 bird bones and land shells, with the more or less perfect preservation of the 

 latter- and the occurrence of turtle-eggs, is strong confirmatory evidence 

 Under the influence of wind far more friction takes place than when small 

 particles are triturated in water, and their edges become rounded to a much 

 CTeater degree, giving rise to the appearance presented by the Coral-sand rock 

 of Lord Howe. The occurrence of such fossils as the above in a similar deposit 

 at St. Helena caused Darwin to ascribe a like origin to it.* On the other 

 hand, marine shells were not frequently observed m the Lord Howe rock 

 but when present were well preserved, and in some traces of colour were stiii 

 apparent. The presence of turtle-eggs, although not found m nests as 

 described by Jukes on the islets of the Great Barrier, may still be taken as 

 evidence tending in the same direction ; and equally so is the palm impres- 

 sion seen by Mr. Fitzgerald, who says : " Li the inchned stratihed coral, m 

 one place, very distinct impressions were observed of palm-leaves 10 or lo 



"^llre'^'ular stratification, and false beddingt were not observed, although it 

 is often asserted that they are features in a^olian rocks; but they are as 

 often seen in aqueous sediments, the result of ever-changing currents. 

 Indeed it is not imperative that false bedding should be present, because 

 Professor H, N. Mosely mentions the entire absence of it in the calcareous 

 sand-rock at Baine Island.§ He says :-The deposit is "closely simi ar to 

 that at Bermuda, except that it is remarkably evenly bedded. It woukl have 

 been much more satisfactory could I have adduced evidence of one ot those 

 temporary m-owth stages of vegetation sometimes met withm asolian deposits, 

 andropreseiitedby bedsof lignite, or someform of carbonaceous matter. Mr. 

 C S Wilkinson has described one in the consolidated sand dunes between 

 the Parker Eiver and Cape Otwav, Victoria. 1| Another instance is recorded 

 by Mosely as seen at Bermuda in a dockyard excavation where a bod of 

 lignite occurs forty feet below sea-level in the sand rock of the island.'^ 

 And lastly Tenison Woods records an excellent case m connection with 

 the Wide Bay sand hills.** No such instances as these have been seen at 

 Lord Howe, although it is not impossible they may occur 



The balance of evidence may, I think,be said to weigh m favour ot the feohan 

 origin of the Lord Howe Coral-sand rock; anditis remarkable how well L>anas 

 descriptiontt of deposits termed by him "Drift Sand-Eock" tallies with it. 

 " Still another kind of beach formation is going on m some regions through 

 the agency of the winds in connection with the sea * * * and proceeds 

 from the drifting of the sand into hillocks, or ridges, by the winds iho 

 drifts resemble ordinary sand drifts, and are often quite as extensive 

 * * * These sand-banks, through the agency of mfiltratmg waters, tresh 

 or salt, become cemented into a sand-rock, more or less friable, which is 

 frequently oolitic. The rock consists of thin layers or lamma), which are 

 very distinct, and indicate, generally, every successive drift of sand ^>hich 

 puffs of wind had added in the course of its formation. As regards the 

 heicrht to which the Coral-sand rock extends, it in no way exceeds the known 



O ^ ■ ' 



* Geol. Obs. Vole. Islands, 1884, p. 88. 



+ Hill's Lord Howe Island, loc. cit. p. 44. . , , , ^ <- ii,;,. 



X The dip, although variable, is too steady over considerable areas to represent this. 

 § Notes of a Naturalist, &c., 1879, p. 347. . , -„ , j- .i n- „f„,.r„rl 



\\ Eeport on the Geology of the Cape Otway District. Eeport of the Director, Geol. 

 Sm-veyVict., June, 18G3-Sept- 1864. [1804-65] p. 25 ,oc, .,-r rn 



li Notes, loc. oil, p. 21. ** Jour. E. Soc, N. S. W ales, 1883, x^ i, p. GO. 



tt Corals and Coral Islands, loe. cit., p. 154. 



