Sec. ii] PAST THE MAO-MEI OASIS AND ITS OUTPOSTS 41I
little fort was protected by an outer gate with walls 17 feet thick. In continuation of this runs the southern wall of an outer enclosure, undoubtedly a much later addition, built with walls only Io feet thick and about I2 feet high to the foot of the parapet. The latter is built of bricks set vertically and betrays its very late date by traverses intended to offer protection against enfilading. It appeared to me very likely that an ancient stronghold had been utilized here to serve as the nucleus of a small fortified station of much later date. As the soil here was a soft clay and had suffered no erosion, little pottery debris was to be found, and no definite evidence could be drawn from it. My general impression of the ruins above described was that they mark the position once occupied by a garrison that was intended to protect the passage along the Etsin-gol close to where the Han Limes crossed the river.
On May 16th we crossed the river, whose bed was here over a mile wide but at the time held Crossing
water only in pools, to the narrow but well-tilled strip of cultivation along its left bank. From the to left bank
farms of Ssû-fên where we reached this, I searched in vain for any traces of the Limes agger along
the narrow gravel glacis immediately above the fields and then among the low broken ridges of
sandstone higher up. Nor were any traces of it seen while we marched on for about five miles over
the gravel glacis overlooking the smiling fields of Êrh-chia-miao.
But when we reached the ruined tower T. XLVIII. a, which was visible from afar, perched on Limes
a little outlying spur some eighty feet above the foot of the Sai, the straight line of the com- towers
pletely decayed agger caught the eye at once. As a low yet distinct swelling on the gravel-covered a, b.
glacis of the hill chain, it could be seen coming from above Ssû-fên with a bearing of N. 40° E. and then turning at T. XLVIII. a in the direction of N. 58° E. The swelling was so low that while
we moved close and more or less parallel to it over the uniform gravel surface, it had necessarily
failed to attract attention. The tower T. XLVIII. a, broken down to a height of only 9 feet, clearly belonged to the time when the Han Limes was constructed. Its base measured 24 feet square, and
the bricks of which it was built were of the regulation size of 14" x 8" x 5". Scarcely any refuse
was to be found on searching the stony slopes below either this tower or the next, T. XLVIII. b, towards which the line of the decayed agger was leading. But of this the explanation is easy.
Neither the men guarding the border nor the ` military Babus ' looking after clerical business
on it would make their quarters at watch-stations when far more comfortable shelter could be
found on cultivated ground within half a mile !
We followed the line of the wall in the direction indicated along the foot of the Sai for over a Decay of
mile, and after a short descent to the verdant fields and shady elms of Hsia-ming-tzû, the last we Limes agger.
were to see for a time, picked it up again without difficulty. It was just visible as a straight swelling
of the ground leading towards the tower T. XLVIII. b, which was reached at a distance of close on
four miles. The Limes agger had almost completely decayed here, as it had also done near the con-
fluence of the Pei-ta-ho with the Kan-chou river, where in September it was searched for without
success by one of the surveyors. This decay may be accounted for by the effect of the drainage
descending periodically from the hill chain whose low outlying spurs here closely approach the
river-bed. T. XLVIII. b (Fig. 225) was found to be a tower solidly built of stamped clay and rising
to a height of 24 feet in comparatively excellent preservation. It measured 20 feet square at its
base and with its slightly conical shape recalled T. III, vii and other watch-towers seen on the
From the steep ridge on which this tower stands, the line of the agger was clearly seen to turn Eastward
to N. 83° E. and to run on straight for about a mile, reaching the left bank of the river-bed just turn of
where this divides into two branches and greatly increases its width. So there could be no doubt that
the Han Limes here, below the northernmost point of the actual cultivation of Mao-mei, had taken
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