afril— -SEPT. 1859.] On the Geology of Thayet Myo, 57 



The two former are doubtless of recent origin. I am not so 

 sure that No. vii is. 



Mr. Oldham, as before remarked, would refer it to the older 

 tertiary formation. I am not competent to give an opinion. It 

 is full (it will be observed) of small organic remains, the nature 

 of which I have failed to deteimine, but which, though smaller, 

 appear to be identical with those in specimen No. ii,* and which 

 appear in oval or elongated bodies of tubular structure radiating 

 from a central line thus a cross section presents the fol- 



lowing appearances <^S^> viz. tubes radiating from a common 

 centre. I will not speculate upon their nature, but confess my 

 ignorance and request information, and also as to the proba- 

 ble position the rock holds in the geological series. With the 

 exception of these rocks, I possess none referable to the imme- 

 diate neighbourhood, sandstones and marly beds also occur, and 

 the general dip appears to be about 30° south south-east with a 

 strike nearly north and south. 



Having lately visited the Military posts of Yamuth and Meng- 

 doon, the former about 28 miles due west, the latter 45 miles 

 west, I may remark that the only rocks met with, from which the 

 general dip and strike could be determined, and specimens pro- 

 cured, were found to consist of limestones and sandstones, shales 

 and seams of coal. No. 1 specimen is a limestone found in a 

 thick bed, with a strike nearly N. and S. and dipping 30° S. S. E. 

 near Alay-gyoing. It contains organic remains of the same 

 (naked -Moluscus ?) character (see particularly the polished sur- 

 face of No. 1), and is a compact variegated marble. 



A few miles (2 or 3) beyond the locality of this limestone ; 

 sandstones were met with (specimens 2 and 3) cropping out in 

 the bed of a nullah and dipping at an angle of 40° and 45°, with 

 a strike nearly due north and south. These beds contained no 

 organic remains, but appeared of great thickness. No further 

 rocks appeared till we reached Mengdoon — 6 and 7 are specimens 

 of the rock exposed upon the river's bank at that station. 



8, 9, 10, 11, and 12, are specimens of the rocks associated with 

 the bands of coal found beyond Youbalay (about 2 miles N. W. of 



* Found near Mengdoon. 

 Vol. xx. o, s. Vol. vi. n. s. 



