On the Tenasserim Coal Field. 425 



short distance., as at b c on the other face, they are hardened by 

 contact with a dyke of igneous rock, which shews itself at C in the 

 line CD. At^? soft shales with seams of under-clay and coal are 

 found, at d a seam of coal crops out at the level of the river, which 

 being at the same level, belongs without doubt to the same beds 

 which are indicated on the other side of this tongue of land at d. 

 The beds upwards from d consist of striped, blue, and soft grey 

 shales, the whole resting uniformly upon each other, and dipping at 

 an angle of 12° up the stream, or to the eastward till we arrive at the 

 point O, where there is another igneous dyke, and the strata are 

 thrown down thereby to the eastward at an angle of 30°. These 

 were followed as far as the point S in the Yaibon river, to which 

 they continue at the same high angle, but beyond this, and for some 

 distance higher up the Yaibon, all trace of them is lost. 



19. The correspondence of the bed C Q, d d, of the dykes C C, 

 O O, and faults S S and the phenomena accompanying them leaned at 

 once to the inference, that the edges of rock, as seen along the lines 

 CD, A B, present two views of the same beds, that their angle of 

 greatest dip is 12°, and that they are continuous from one side of 

 this tongue of land to the other. In examining the country inland, 

 the dyke o was distinctly marked at various points between o and o, 

 and its direction is shewn on the plan. Igneous rock was also found 

 at intervals between CYC, denoting, that though these igneous dykes 

 passed through the coal field and disturbed the continuity of the beds, 

 they remained between the two dykes and across the tract between 

 O C, C O, unbroken, and resting on one another with great regularity 

 at an angle with the horizon varying from 7°, 9° to 12°. The 

 space covered thereby is If miles in length by 400 yards in aver- 

 age breadth. 



20. The bed of coal at d d I believe to be of the same thickness 

 and quality as that which has been worked at the mine. There is in 

 the bed of the stream near the opening of the mine at I, the fractured 

 edge of a ferruginous rock distinctly marked, which dips immediately 

 below the coal at the same angle with it, and has been forced up at 

 the same period. The bearing of this edge is 2| degrees East of 

 North, which is denoted by a black dotted line in the plan. The posi- 

 tion of the outcrop of coal d, which was arrived at by observations 

 independent of the line of bearing alluded to, is as nearly as possible 

 upon this line, and the coal shewn at these two points formed, I con- 



