38 



Island. Several uncharted shallow patches were then discovered, 

 and a prof essional pearl-shell diver being employed to investigate 

 their nature, ascertained that they consisted of recently formed and 

 growing coral. These ])atches are somewhat out of the accustomed 

 track of the ordinary mail steamers, and are at present of insuffi- 

 cient altitude to constitute a danger to passing shipping. It is 

 anticipated, however, that within a few years' time, they may so 

 increase in proportion as to fall within this category, and I 

 have reccommended that their p.isitiou should be marked, and 

 a periodical investigation made, in order to determine the rate of 

 growth and altitude of the corals of which they are composed. 



Apart from the vital processes by which reefs and their compo- 

 nent corals are continually adding to their bulk, there can be but 

 little doubt that a slow motion of upheaval is progressing through- 

 out the region of Torres Straits and the great Barrier system, 

 and this too must tend towards rendering the older charts 

 untrustworthy. The coral reefs volunteer their own evidence upon 

 this point. At many stations throughout this region, the circum- 

 stance may be noted that large expanses of dead coral intervene 

 between high water mark and the living banks. This 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 iii siiu as it originally grew, 

 and is only lacking in vitality to distinguish it from the living 

 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 afrini;ing coral reef, the living inner 

 margin of which, composed chiefly of a branching Madrepora, 

 is only exposed at the lowest sj)riug tides. Immediately 

 adjoining 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 l)roken up, by the 

 action of the waves and chemical disintegration, and be added to 

 the existing inshore area of coral mud and debris. An examina- 

 tion of the circumstances that have brought about the present 



