BY E. C. ANDREWS. . 153 



the only continental rocks now visible are those to be found at 

 tlie nortliern island extremities. 



Frazer Island likewise appears to be composed of sand. In all 

 cases these islands are associated with large rivers and coastal 

 plains. They have straight eastern coast lines 50 or 60 miles 

 long, while straight or swinging sandy coasts with enormous coast 

 plains, lagoons, creeks, monadnocks, lagoon-marsh meadow^s, and 

 w ith ,2;ently sloping off-shore deposits constitute the chief features 

 of the neighbouring mainland. 



Near the mouth of the Fitzroy River numerous insular patches 

 occur, the longest of which is Curtis Island, running parallel to 

 the mainland, and separated from it by a long narrow channel, in 

 wliich the variation in the tides amounts to as much as 27 feet. 

 This island is composed in great part of sfind; it contains signs of 

 elevated beaches,* and is associated with extensive coastal plains. 



The Beverley and Northumberland Groups comprise numerous 

 small rocky and pine-clothed islands, usually presenting mural 

 fronts to the sea — the result of marine erosion. 



In the Whitsunday Group are islands of considerable size, 

 separated from each other and the main coast by narrow channels 

 of great length. 



* As no notice of this has appeared in literature, Iledley supplies the 

 following note : — 



" A striking instance of apparent elevation was shown to me by Mr, J. B. 

 Paterson, the lessee of Curtis Island, Q. A few miles south-west of the Cape 

 Capricorn Lighthouse occur what are locally called the Marine Plains. 

 These are an extensive series of swampy Hats, some miles inland, occupying 

 bays in the hilly country and margined by a continuous beach-bank, com- 

 posed of sand and recent sea shells. Within the bays are small rocky 

 ' islands ' with wave -eroded flanks, and also encircled with beach-banks. 



" When I saw' it fifteen years ago this scene impressed me as indicating a 

 recent and slight upheaval. But further study of beach-formation convinces 

 me that elevation is not the only possible explanation of the phenomena 

 described. Should the entrance of a shallow bay become blocked by beach- 

 banks or dunes, the consequent shutting out of the sea might leave the head 

 of the bay in such a condition as the Marine Plains of Curtis Island, without 

 the intervention of elevation." 



