BY HENRY 0. RICHARDS, M.SC. 201 



This tuff is not of uniform compactness in all the quarries 

 or even in the same quarry, and requires to be carefully 

 chosen, but when well picked and dressed properly, is found 

 to be a highly durable stone under the local climatic con- 

 ditions. 



(2) HELIDON SANDSTONE. 



This stone is also well known in Brisbane, having been 

 used in many structures. 



There are several varieties, white, pink, and brown. 

 The Lands Office affords the best instance perhaps of a 

 structure of the brown stone, while in the Central Station 

 buildings, the white and also the pink varieties may be seen. 

 The former building, with the exception of the columns 

 and the stones above them, which are of Yangan material, 

 is of the brown Helidon stone, the basement being of granitic 

 stones from Enoggera and Mount Crosby. The brown 

 variety is a particularly handsome material, works well, 

 occurs in large blocks, and has a warm tone in contrast 

 to the cold, hard effect of the white variety. The concentric 

 markings due to the iron-staining, together with the 

 variation of iron-contents in the different blocks give a 

 structure of this material a vej'y pleasing effect, particularly 

 when compared with buildings of a uniform grey stone, like 

 the Treasury Building. 



All the interior work of the Cathedral, the walls, ceiling 

 and pillars, is done ^^itll this stone, and an examination 

 of this building shows the possibilities in working this free- 

 stone. 



Owing to its protection from the weather, not the 

 slightest fear need be felt as to its endurance. 



The stone was obtained from Wright's quarry, and 

 the following information on the brown stone used in the 

 Government Printing Office, and now being used in the 

 Central Technical College buildings, has been very kindly 

 supplied by Mr. T. Pye, the Deputy Government Architect: — 



Compression Strength. 



Building. Lbs. per sq. inch. Tons per sq. ft. 



1. Government Printing Office . . 5355 344.25 



2. Central Technical CoUege . . 5076 326 



3. Central Technical College . . 3624 233 



Numbers 1 and 2 were dry, while 3 was wet. 



