Geological Society. 311 



Analyses by M. Pisani. 



Hebron. Montebras. 



Fluorine 5-22 3*80 



Phosphoric acid 48*65 47*15 



Alumina . .- 36*00 36*90 



Lithia 9*75 9*84 



Water 4*20 4-75 



101*82 102*44 



Specific gravity .... 3*03, Pisani. 3*01, Pisani. 



2*99, Daniour. 2*977, Daniour. 



Wavellite, in the form of thin coatings, forms a layer over 

 almost all the fissures that occur in the amblygonite of Montebras. 

 In cavities in these coatings are found long thin needles, which 

 have enabled the author to correct the older measurements of this 

 mineral. 



M. Pisani has ascertained that the variety from Montebras 

 yields : — 



Fluorine 2*27 



Phosphoric acid 34*30 



Alumina , 38*25 



Water ' 26*60 



101*42 

 Specific gravity 2*33 



GEOLOGICAL SOCIETY. 



[Continued from p. 235.] 



November 6, 1872.— Prof. Ramsay, F.R.S., V.P., in the Chair. 



The following communications were read : — 



1. " A Report by F. T. Gregory, Esq., Mining-land Commissioner 

 in Queensland, on the :ecent discoveries of Tin-ore in that Colony." 



According to this report, the district in Queensland in which tin- 

 ore has been discovered is situated about the head-waters of the 

 Severn river and its tributaries, comprising an area of about 550 

 square miles. The district is described as an elevated granitic 

 tableland intersected by ranges of abrupt hills, some rttaining an 

 elevation of about 3000 feet above the sea. The richest deposits 

 are found in the beds of the Screams and in alluvial flats on their 

 banks, the payable ground varying from a few yards to five chains 

 in extent. The aggregate length of these alluvial bands is esti- 

 mated at about 170 miles ; the average yield per linear chain of the 

 stream-beds at about ten tons of ore (cassiterite). 



Numerous small stanniferous lodes have been discovered, but only 

 two of much importance — namely, one near Ballandcan Head Station 

 on the Severn, and another in a reef of red granite rising in the 



