VII.— The Disai Field. 



My examination of the Disai field is very incomplete^ having been 

 made before any maps of the ground were availably. 



The coal measures occur in the neighbourhood of Japu^ near the 

 base of the ridge on which the village is situated, and also in the bed of 

 the Disai itself. They are flanked on both sides by Sub-Himalayan 

 rocks, which overlie them on the south and are faulted against them to 

 the north. There is a considerable amount of irregular disturbance by 

 which the strata are inclined at various angles and in different directions : 

 the prevailing dip is about south-30°-east. 



The eastern extension of the field is uncertain. Most probably the 

 fault along the northern boundary is continuous with the main fault in 

 the Dikhu and Janji, in which case it is not unlikely that the measures 

 might be found at the head of the Tiru nadi. But somewhere east of 

 the Disai they are cut off, as the Disang and Tipam groups are in 

 contact in the Janji. How far the coal rocks extend to the west up the 

 Disai valley is unknown, but the comparatively few pieces of coal 

 to be seen in the river near Japu, and their small size, would not 

 lead one to expect a very great development of the measures higher 

 up stream. 



About half a mile from the Disai, up a small lateral stream north-30°- 



west (?) of Japu, five or six seams, associated with 

 Coal outcrops. . . , . . 



grey shales and sandstone, are visible withm a 



distance of about 30 yards. One is 4 feet thick, another 3, and others 



vary from 6 to 18 inches. The dip is about east-30°-north at 60°, but 



is irregular. The coal is soft and much crushed. 



( 344 ) 



