848 GEOLOGY OF GLASS HOUSE MTS. AND DISTRICT, 



dwarf gums, orchids and mosses. Mt. Beerwah, the loftiest cone 

 of the group, is only 1,760 feet high; Mt. Conowrin 1,170 feet; 

 Mt. Tunbubudla 1,020; all the others being below 1,000 feet. 

 They are all of a steeply conical, sugarloaf form, composed of 

 trachyte which is for the most part columnar. The most southerly 

 member of the trachyte cones that I have been able to find is 

 the Round Mountain, a hill about three miles W. of Cal)oolture; 

 the most northerly, Coochin Mountain, near Beerwah Railwa}' 

 Station. 



Those mountains which rise directly from level country, e.g., 

 Tibrogargan. Tunbubudla, and Miketeebumulgrai, are surrounded 

 by a gutter of boggy country, a few hundred yards wide, round 

 which a sandy ridge, often with sandstone outcrops, is met with. 

 This gutter, which is studded with "paddymelon" holes, may 

 be due to a slight subsidence caused by the weight of the moun- 

 tain, perhaps accompanied by faulting (a cauldron fracture), or 

 it may be due to the wash of water down the steep sides of the 

 mountain in rainy seasons. 



(c) Miscellaneous Notes Oil Physiography. — A noticeable feature 

 in the East Moreton district is the close correspondence between 

 vegetation and geological formation."^ 



On the sandstone formation, oaks (Casuarina) are very plenti- 

 fully distributed amongst the gums, and the grass-trees have 

 trunks. 



Where the soil is clayey, overlying shale, wattles are inter- 

 spersed amongst tall straight gums and stringybarks. 



On the ash}^ caking soil from decomposing trachyte, vegetation 

 is very scanty, consisting of crippled tea-trees and stemless grass- 

 trees (Xanthorrhcea). On the trachyte formation oaks are 

 typically absent, but often a trachyte dyke is marked by a row 

 of tall gums and oaks, which have here sufficient food as well as 

 good drainage. 



* Cf. Mr. Maiden's Presidential Address to the Linnean Society of New 

 South Wales, Proc. 1902, p. 682. 



