I30 THE GREAT BARRIER REEF. 



stranded nature as those represented in Plate XXX. of this volume, and the intrinsic 

 lightness of the pumice-stone would allow of its being blown during a hurricane, with the 

 ocean foam, far above high-water mark. The small significance which Mr. Jukes himself 

 attached to this evidence is made manifest in his final verdict concerning the Barrier's origin. 

 In this he explicitly states : " I tried hard to find any substantial objection to this [Mr. 

 Darwin's] hypothesis, and must confess I failed to do so. After seeing much of the Great 

 Barrier reefs, and reflecting upon them, and trying if it were possible, by any means, to 

 evade the conclusions to which Mr. Darwin has come, I cannot help adding that his hypothesis 

 IS perfectly satisfactory to my mind, and rises beyond a mere hypothesis into the true theory 

 of coral-reefs." 



Some attention was recently given to this subject by Professor A. C. Haddon during his 

 sojourn in Torres Strait, but, as recorded in a paper on the geology of the district,* without 

 his discovering any tangible evidence indicating a movement of upheaval. The author has 

 been on the outlook for such testimony, during several years' investigation of this region, 

 but with negative results, so far as evidence indicating any extensive upward movement was 

 concerned. These investigations, nevertheless, elicited testimony indicative, apparently, of 

 a slight local elevation of the coast-line in certain well-defined areas. This evidence, which 

 was originally embodied by the author in his presidential address to the Royal Society of 

 Queensland, for the year 1890, is here reprinted verbatim. — 



" At many stations throughout the Barrier region, the circumstance may be noted that large 

 expanses of dead coral intervene between high-water mark and the living banks. The dead coral 

 here referred to, is not the broken debris that has been cast up by storms, such as commonly exists 

 all along extreme high-water mark, but occurs at a lower level, /// situ, as it originally grew, and 

 lacks vitality only, to distinguish it from the growing reefs. The Albany Pass, between Cape 

 York and Albany Island, yields a prominent illustration of this phenomenon. On either side of the 

 passage there is a fringing coral-reef, the living inner margin of which, composed chiefly of a 

 branching Madrepora, M. millcpora, is only exposed at the lowest spring-tides. Immediately ad- 

 joining this living bank, between it and the foreshore, there is a belt of the same species of coral, 

 but entirely dead, and brittle, like rotten ice, to walk upon. Within a few more years, this dead 

 belt will no doubt be broken up, by the action of the waves and chemical disintegration, and be 

 added to the existing inshore area of coral mud and debris. An examination of the circumstances 

 that have brought about the present condition of the reef, show that this dead belt of coral is novv 

 exposed to atmospheric influences which are antagonistic to its growth, with every ordinary spring- 

 tide ; while the living coral, as before observed, is only visible above the water at the exceptional 

 or lowest springs. At such period as the inner belt of dead Madrepora was alive, and that from 

 its state of preservation cannot have been long ago, it must have grown at a similar lower level 



* Prof. A. C. Haddon, " Notes on the Geology of Torres Straits." Report British Association, p. 587, 1889. 



