Geological researches in China, Mongolia, and Japan, during the years 1862-1865.

14 GEOLOGICAL RESEARCHES IN
and porphyry, shows that these older rocks had been subjected to an extensive
denudation.
In the narrow gorge, through which the creek finds its way from the Chaitang
valley to the Hun river, the contact between the limestone and porphyry conglomerate is visible (Fig. 1). The limestone strata
are cut through at a right angle, and are seen to
o — _Fig. 1 a i / dip about 800 to the S.
0 ~ 0 0 1 //l 1/ 1 I did not obtain an observation of the dip of the
0o ~ c -,////////l conglomerate in this section to know whether it
B A ^ n /// / / 11I
C v "'!o////,/ //,I conforms to that of the limestone.
O ~ a D,/Z/,i/////>/// / / ^The coal district of Chaitang forms an area of
low hills, and is limited on the north by the pora. Upper limestone.
b. Lower porphyry conglomerate. phyry conglomerates, whose high and rugged hills
are overtopped in the background by the yellow
cliffs of the limestone. To the south rises a high ridge consisting, apparently, of
the rocks of the Coal measures and dykes of porphyry, and separating the coal
district of Chaitang from that of the Wangping creek. To the west is a high and
hilly country mainly of porphyry.
About four miles W. N. W. of Chaitang, in the midst of this porphyry, lies the
small coal district of Chingshui, and about five miles S. W. are the anthracite
mines of the Tatsau district.
The valley of Chaitang has been occupied by a lake, the alluvial deposits of which
now form terraces and cap hills over one hundred feet high. The trend of the tilted
strata in the centre of the district is very uniformly N. W., and the dip is to N. E.
and to S. W., forming both synclinal and anticlinal ridges. But as we approach
the western end the trend becomes irregular, though the dip is toward the porphyry.
Indeed, the edge of these mountains of porphyry, seems to mark the line of a great
fault, perhaps combined with an immense overflow of that rock.
The following description of the more important coals is extracted from my
Report to the Chinese Government, which is published in the " United States Diplomatic Correspondence, 1864, Part III."
For more perfect analyses of some of these and other coals by Mr. J. A. Macdonald, the reader is referred to Appendix No. 2.
Principal Mines.-The Futau mine, which lies about five li (less than two miles)
S. S. E. of Chaitang, and from one hundred and fifty to two hundred feet above
the level of the creek at that town, is remarkable as producing a "steam coal" that
is equal if not superior to the best Welsh variety.
The seam, in which several openings have been made, is irregular in thickness,
this varying from six to twelve feet, though in the mean averaging, probably, not
less than seven feet. Near the roof the coal has a tendency to crumble, near the
floor it is slaty; all the rest of the seam furnishes large blocks of firm and excellent
fuel.
The coal has a brilliant lustre, is made up of well-defined layers, and has a tendency
to a cubical fracture. It ignites quickly, burning with a long flame and little smoke.