10 GEOLOGY. 



the banks of Pagaya river which crosses it, show clayslate crop- 

 ping out below the alluvium which is remarkable for contain- 

 ing a large quantity of small iron pyrites. Specimens of this 

 slate after being in the cabinet one rains, were covered with 

 a thick efflorescense of sulphate of iron, or copperas, from 

 the decomposition of the pyrites. The hill at the village of 

 Salung* which bounds this plain, is formed of claystone por- 

 phyry, soft, and of a bluish color, where not exposed to the 

 weather. The little knoll a mile further east, on which the 

 village of Ta-laing-doungf stands, appears to be formed of clay- 

 stone. Soon after this white sandstone appears, and half a mile 

 beyond, Nga-than-kyoungf is seen running over a ledge of 

 white sandstone rocks. The same rock appears at intervals 

 for two miles farther to a little distance east of the village of 

 Pyee-doung,§ where an igneous dyke crops out of the bank of 

 the river that has been called, but it is believed erroneously, 

 grauwacke. 



The hill east of Pyee-doung is formed of claystone porphy- 

 ry of a reddish color, and more indurated than that at Salung. 

 A small hill beyond has slate clay, and furnishes all that is 

 seen in Tavoy bazar ; and a hill east of this, shows claystone 

 porphyry again near the mouth of Bya-hung-khyoung.|| Be- 

 yond this, a micaceous-slaty sandstone is seen cropping up a- 

 cross the road, and a few hundred yards farther east, common 

 white sandstone is seen in the banks of Pagaya river. These 

 sandstones appear near the base of a range of hills from five to 

 eight hundred feet high, that reach Pagaya river at its forks 

 aj!x)ut nine miles from Tavoy. This range seems to be wholly 

 composed of thin lamina of slate, principally clayslate, in some 

 places much contorted. Dr. M'Clelland designated one speci- 

 men that was sent him as " chlorite slate." The strata make 

 an angle with the horizon of about 30°. East of this range, clay- 

 stone porphyry appears again, and beyond this in the bed of a 

 little stream, limestone apparently stratified shows itself, the 

 beds making an angle of from 20° to 30° with the horizon. 



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