THE CENTRAL RANGE MINES. 293 



are in granite close to its contact with the argillites. The veins, 

 which as far as is known to-day, are not so numerous nor so strongly 

 developed as those on that mine, yet possess the same approximate 

 strike and general characteristics, cassiterite greisens bordering them 

 being a common feature. All the concentrates are rich in tinstone. 

 J land mining and ground sluicing are carried on. 



Hteinthit. — To the south of Taungpila No. 2, and still following 

 the granite contact, is the Hteinthit mine of Mr. (i. X. Marks. 

 Though unimportant as a producer, this property is very interesting 

 from a geological point of view. Jts production for the past few 

 years is given below : — 



Tuns. 

 1915 6 



1916 . 8 



1917 . 4 



1918 \1 



The concentrates contain a high percentage of cassiterite and 

 are won by sluicing and from a few small veins. 



The granite contact runs from north to south of the area approxi- 

 mately along the course of the Hteinthit stream, dividing the conces- 

 sion into two parts : the western two-thirds are in the Merged sedi- 

 mentary series, the eastern portion is in granite. On the western 

 hill there are two narrow veins, eight inches and five inches in thick- 

 ness, in greatly disturbed argillites. The veins themselves are 

 twisted so that the strikes vary from east 10° north, west 10° south 

 to east 30° south, west 30° north. The dip is towards the north 

 at 60°. Slickensiding of the walls is common and the larger vein 

 is cut off by a cross vein which meets it at approximately 90°. 

 These veins are well mineralised, the recovered content being about 

 2 per cent., of which 60*70 per cent, is cassiterite in the larger vein. 

 On the other side of the valley three veins are known in granite. 

 They strike north 10° west, south 10° east and have a high dip 

 towards the east. They contain wolfram and no tinstone. We are 

 indebted to Mr. E. Maxwell Lefroy for these data. 



S7i6JjU£ld.— Sheffield mine lies to the south of the Hteinthit 

 concession. It has a large surface area and stretches right acrusa 

 the intrusion, thus including both its eastern and western contacts. 

 It was held at first under a prospecting license by Kyon Nga, from 



