422 MIN ERA LOG I CAL DESCRIPTION OF THE ISLAND OF DANKA. 
2. Black-clay, massive as observed in the other 
mines.... 8 feet, 
3. Clay of a greyish colour containing a small pro¬ 
portion of sand.. ... 4 ,, 
4. Black-clay, irregular massive. 6 „ 
5. Coarse sand in transparent grains bedded in 
pure white clay... 3 ,, 
This extended to near the stratum containing the ore of tin. One 
of the miners with a long crow-bar raised a portion of it and pro¬ 
duced to me some of the ore of tin : they were employed in carry¬ 
ing out the last mentioned stratum. 
In the west. 
1. Stratum, vegetable mould. 
2. Black-clay, massive. 
3. Sand in clay of a grey colour. 
4. White sand. 
5. Beautiful white sand (of transparent siliceous particles) and 
clay. 
6 . Sand bedded in yellow clay. 
7 . Sand in dark bluish clay. The last three layers were less re¬ 
gularly horizontal in their disposition, than the layers of sand in 
many other mines; they had considerable inclination. 
8 . Loose white sand. 
9. Yellow sand, coloured with particles of clay, but scarcely ad¬ 
hering ; on this followed : 
10. The stratum of coarse fragments of decomposed granite, 
and of breccias through which the ore of tin was disseminated. 
None of the mines I visited afforded me a more beautiful and dis¬ 
tinct view of the succession of the strata, or more explanatory of 
their arrangement. The pit on which the workmen were employed 
had been formed with uncommon neatness, and by means of the 
abundance of the clayey particles the sides had remained completely 
regular and perpendicular. The last layer (No 9 just mentioned) 
of yellow sand contained delicate streaks of the ore of a black colour, 
(consisting of very minute particles) which became evident when it 
