314 LATOUCHE: GEOLOGY OF NORTHERN SHAN STATES. 



of the same material radiating in all directions from it, but most 

 highly developed towards the west and north-west, where there 

 may be another focus of eruption. This hill appears in the centre 

 of the view of Loi Ling (Plate 1). It is from these dykes that 

 the boulders of dolerite, mentioned by Mr. Simpson, which choke 

 every stream bed in the neighbourhood, have been derived. No 

 amygdaloid rocks were seen on Loi Han Hun itself, but their 

 occurrence in the vicinity seems to show that some lava actually 

 flowed from it. Otherwise the energy of the volcano appears to 

 have been just sufficient to extrude the dome of basalt now form- 

 ing the upper part of the hill and to fill the fissures surrounding 

 it, no traces of a true cone built up of ashes or tuffs being visible. 



The rock of which the dome is composed is a dense basalt, 

 almost black in colour with a greenish tinge, 



Petrographical char- consisting of an aggregate of minute lath- 

 act ers. b tot> & 



shaped crystals of plagioclase felspar and 

 minute granules of augite, in which large crystals of plagioclase 

 with zonal inclusions of the ground mass, much magnetite, 

 and granular crystals of olivine are disseminated. 1 (Plate 7, 

 fig. 2.) 



(vi) Man-se-le field. The last of the Tertiary basing to be 

 described covers a very wide area, but only a small 

 portion of it, the Man-se-le coal-field of Mr. Simpson 

 (op. fit., p. 152), is known to contain coal seams. This 

 area is situated on the east side of Loi Ling, covering 

 the greater part of the valley extending southwards 

 from the base of the hill to the Nam-Pat, an area of 

 about 36 square miles (J 2). Beds of coarse sandstone 

 are more common than in the Lashio field, but other- 

 wise the rocks are similar. Several seams of coal were 

 met with, but none of them appear to be of economic 



„., . , value, at any rate for many years 



White-clay. ^ , , , , 



to come On the southern bound- 

 ary of the field, near Mankiin, is an interesting exposure 

 of white kaolin-like clay, similar to that at Man-Se in 

 the Namma field. At this place the clay appears to 

 have filled a fissuie in the limestone floor of the basin 



1 La louche, A Volcanic < hit burst <>t laic Tertiary a^e, etc.; Rerotds, Geol. Surr. hid., 

 Vol. XXXVI, Pt. 1, p, 40. 



