BY H. I. JENSEN. 873 



parallel to the main north and south fissure of the Glass House 

 Mountains. Basalt-flows, producing fine rich soil, have taken 

 place from many points along this range. 



The basaltic mountains of the East Moreton are easily dis- 

 tinguished from those composed of trachyte by the pretty gentle 

 slopes, and rich tropical vegetation of the former. The Bankfoot 

 House andesites seem to have been very fluid, much more so than 

 the Mellum basalts. They have not given rise to any cones, but 

 have flowed over sandstone formation and small trachyte outcrops 

 alike. 



In connection with the question of land-formation by the sea 

 in Moreton Bay is the possible explanation of the shell-banks 

 inland on the hypothesis that the sea has piled up bank after 

 bank and thus retreated, Mr. H. L. Kesteven writes as follows: — 

 "During September, 1902, I had the opportunity of going 

 through Bribie Passage and of examining in a cursory manner 

 the country on either side of it. The 'Passage' runs between the 

 mainland and Bribie Island. This island is wedge-shaped, about 

 17 miles long, and 3| miles broad at its broadest, southern, end; 

 the greater part of it is but three or four, nowhere is it above 15 

 feet high. Its higher parts are blown (?) sand, and the lower 

 black sandy mud. I was busy collecting mollusca, so did not 

 have an opportunity of going over it thoroughly, but there is, I 

 believe, no rock on the island anywhere. North of the high land 

 at Toorbul Point, the mainland is of the same character. 



" Some very interesting light was thrown on the growth of 

 this low-lying country by Mr. C. Tripcony, in whose boat I went 

 up the Passage. 



"Owing to the strong current in the Passage, the bottom is 

 continually shifting and changing the channel; the troubles of 

 navigation were the subject of much conversation. Mr. Tripcony 

 has owned oyster-beds in and sailed up and down the Passage 

 for about twenty-five years. In the course of conversation, he 

 pointed out to me an islet about two feet high at high tide, which 

 he assured me did not exist in his early days on the Passage; on 

 another occasion he drew my attention to some mangroves just 



