The great central depression of the continent which reaches from the foot of the Pamir plateau on the west through the Tarim desert to Lop Nor and the Gobi has yielded up many interesting Chinese secrets.
He had meant only to lop off a few ultramontane extremists; he succeeded in sending Catholics of every shade and colour pell-mell into the arms of Rome.
Of these Lop Nor and the Helmund hamuns are typical.
His fourth journey in 1883-1885 was to Sining (the great trade centre of the Chinese borderland), and thence through northern Tibet (crossing the Altyn Tagh to Lop Nor), and by the Cherchen-Keriya trade route to Khotan.
There are ampler expanses of hard saliferous clay (shor) and on the north side of the desert of Lop the surface has been carved and sculptured by the wind into innumerable flat, tabletopped masses (jardangs) with vertical or even overhanging sides, separated from one another by deep-cut, wind-swept gullies, running from north-east to south-west.