74 GEOLOGICAL RESEARCHES IN 



Dec. 5. Travellpd over a rolling country chiefly of granite and mica schist. 

 Associated with the latter rock is a white dolomitic limestone in apparently inter- 

 stratified beds, impregnated with specks and flakes of graphite. The general trend 

 of these rocks appeared to be to the N. W. 



The granite had, in places, more the appearance of a metamorphosed conglome- 

 rate breccia than of a true granite. 



In the afternoon we encamped among outcrops of trachytic porphyry identical in 

 character with that of Kalgan. I found here all the kinds seen at Kalgan, includ- 

 ing a striped variety, and specimens with primary quartz. This porphyry contains 

 veins and concretions of chalcedony and cornelian. 



Dec. 6. Our road lay all day over a rolling country, granitic and syenitic rocks 

 prevailing, till in the evening we reached the foot of a picturesque granite peak, 

 the Bogdo oola,^ rising several himdred feet above the surrounding country. To 

 the west of this we saw a large valley with water or, rather, ice. 



An accident detained us here till the next afternoon. 



Dec. 7. Started in the afternoon, and after passing the Lamasery of Churin- 

 chelu, and travelling a few miles along the foot of the Bogdo oola, encamped for 

 the night. 



Dec. 8. Travelled about 20 miles over a rough country. As the ground was 

 covered with snow, I saw but little of its character, the outcrops seen being all 

 granitic. 



Dec. 9. This day we were again on the undulating country of the plateau and 

 the great steppe deposit. Near our camping place were many fragments of volcanic 

 scoriae and of chalcedony, 



Dec. 10. Our road was still on the steppe of yesterday, the surface rising rapidly 

 toward the north. The rolled detritus on the surface was mostly derived from mica- 

 schist, and clay slates, and in a ravine I observed the former rock in place. Near 

 this we entered the hills that limit the steppe, and found them to be of basalt, at 

 least as far as the camping place. 



Dec. 11. This day found us in the range of hills that, trending S. W. from the 

 Kentei mountains, forms the watershed between the steppes of the Gobi and the 

 valleys of the Tula and Orkhon rivers, whose waters flow to the Arctic Ocean. 



The country is here made up of roimded, grassy hills, of about the same height, 

 with valleys remarkable for the regularity of their long, unbroken, cross curves. 

 The hills are of a black, metamorphosed clay schist, and a compact, greenish rock, 

 chiefly feldspar and quartz, apparently a metamorphic greenstone. The strike of 

 the clay rock, where observed, was N. S., and the dip vertical. 



The valley bottoms, and the lower slopes of the hills, are covered with a rich, 

 black earth, the deposit showing no signs of erosion. Our camp this night was in 

 the Horteryndaban. 



Dec. 12. During at least the greater part of the past night we were descending, 

 and daylight found us in a valley much like that which leads from Kalgan to the 

 plateau, viz , a narrow, gravelly descendmg plain, inclosed between hills several 



^ Bogdo, sacred, and oola, mountain. 



