64 GRIMES: MYINGYAN, MAGWE AND PAKOKKU DISTRICTS. 



etc., which are often hollow in the centre ; the larger rounded concre- 

 tions and fossil wood are much less common than in the zone below. 

 4. In the fourth zone we have conglomeratic beds coming in 

 Zone 4. Character of a S ain - At first it is simply small pebbles 

 the component beds. scattered through the sandstone, but this 



gradually passes into beds of conglomerate in which the pebbles are 

 at first small, but increasing in size -as we get into the higher beds 

 until at last we have conglomerates with big pebbles like those near 

 Nyounghla. At the same time as this increase in the size of the 

 pebbles we have an increasing quantity of oxide of iron in the beds ; 

 at first they are only stained by it, but it increases until we have beds, 

 of conglomerate or pebbly sandstone of a deep red or reddish brown 

 colour. In these conglomerate beds there is usually a large amount 



Fossil wood and verter- of fossil vvood > which is mostly much more highly 

 brate remains. silicified than that in the lower Irrawaddi beds. 



It was from conglomerate beds of this zone that Mr. Crawford, 

 Dr. Oldham, and in late years Dr. Noetling have obtained numerous 

 fossil vertebrate bones, but I was unable myself to find any such 

 remains in this zone. 



These last three zones of mine Dr. Noetling has included in one 

 zone, his zone of Mastodon latidens and Hippopotamus irravadiensis. 

 Higher than this Dr. Noetling has another zone, but I did not have 

 any opportunity of examining Irrawaddi beds of later age than those 

 of my fourth zone. 



Resting horizontally on the upturned Irrawaddi beds on the 



Plateau gravel (post- plateau-like top of the Yenangyaung hills, and 



pliocene). Its extent. .■, c l i* <.t- 



consequently or post-pliocene age, there are 

 some patches of gravel which at one time were evidently con- 

 tinuous, but the denudation of the hills and the deep cutting into 

 them of the stream beds has left only a few remnants. Dr. Noetling 

 mapped some of this plateau gravel, and I have found several 

 more patches farther north on the tops of the hills in blocks 

 10N, 12N, 14N, and D of the Yenangyaung oil-field, which 

 extend to the north as far as the Gwe Chaung, but on the north 



' Memoirs, G. S., I., Vol. XXVII, Pt. 2. 

 ( 64 ) 



