380 MESSES. E. HEEON-ALLEN AND A. EAELAND ON THE 



The whole sample was then mixed again and put in 10 per cent, hydrochloric acid, which 

 dissolved out the carbonates. The residue was washed and dried and weighed, and the carbonates 

 estimated by difference. This percentage of loss included a small portion of muddy sediment 

 (clay substance) which was left on the filter-paper. This sediment was black, brown, or grey, and 

 was never more than -5 per cent, of the original weighed sample. 



The remainder was then put in bromoform (density 29) in a separating funnel, and divided into 

 two portions, which were washed and dried and weighed separately. 



Slides were then mounted from each portion of each sample, and the minerals were determined 

 optically. 



The chief constituent of the minerals with density less than 2-9 is quartz, which is at least 

 95 per cent, of this portion. 



Of the heavy minerals, the chief constituent is ilmenite (titaniferous iron-ore), which is quite 

 75 per cent, of this portion, and in some cases more. Zircon is next in quantity, and the others 

 are variable. 



A lot of the constituents are contact-minerals, such as garnet, epidote, kyanite, sillimanite, 

 tourmaline, and cassiterite, and I am of opinion that the sand is formed by the breaking down of 

 a metamorphic gneiss. 



The grains are subangular, which points to the sand not being far removed from its point of 

 origin. 



The samples are practically alike, and only slight differences occur. In addition to the minerals 

 mentioned, there are a few grains of a deep blue mineral, which I cannot identify, but which may 

 be blue tourmaline. There is also a fair quantity in each sample of a reddish-brown mineral, 

 which sometimes shows good prism-faces with an extinction of 30 degrees. It is bi-axial, and the 

 optical sign is negative. I cannot identify this at all. 



Detailed results as follows : — 



Sample No. 1. 



Eetained by 30 sieve .... 20-0 per cent. 



60 „ 2o'0 



90 ,, .... 41-0 

 Passed by '90 , 14-0 



Loss in 1 per cent. HCl . . 50-0 per cent. = Carbonates. 



Lighter than 2-9 49-0 „ Quartz. Microcline. Soda Microeline. Ortboelase. 



Heavier than 2-9 LO „ Ilmenite. Zircon. Garnet. Hornblende. Epidote. Entile. 



Tourmaline. Orthite. Kyanite. Diopside. Cassiterite. 



SiUimanite ? 



Loss in 10 per cent. HCl . . 24-0 per cent. 



Lighter than 2-9 75-0 „ Quartz. Orthoolase. 



Heavier than 2-9 1-0 „ Ilmenite. Zircon. Garnet. Orthite. Eutile. Cassiterite. 



Epidote. Hornblende. Apatite. Monazite. Sphene. 



