Puslapio vaizdai
PDF
„ePub“
[ocr errors]
[ocr errors]

tions without knowing their significance and took them by mistake for regenerated loess, ascribing them to supplementary gatherings of materials on low places. It was only at a later time that I perceived their real significance and observed them in very various circumstances. We might call this formation, the “lake loess,” to distinguish it from the “land loess." We ought a priori to expect that the lake loess would not possess the porosity and capillary vertical structure, which are caused by roots of plants. Indeed these qualities are wanting except in those places where the growth of plants at any time has itself led to the formation of little canals, and thus it is sometimes difficult to distinguish the two kinds of loess from each other. The lake loess however possesses always a stratification, which is entirely different from the bank-like separation of the land loess, and it has a yellowish white colour. On account of its lack of capillary structure it allows water to trickle through with difficulty. Therefore the water flows to it in brooks and small streams and remains standing on it in lakes. It is always very salt and the water in its vicinity undrinkable. Where the loess rises in walls above the bottom of the valley it is covered with salt marks, although in course of time there must have taken place a great washing out of a substante so easily soluble. Such places I shall need farther on more particularly to describe in the south of Shan-si. Generally its upper parts are continued to some distance. While the deepest points of the loess troughs are to be met with, where the salt lake in former times spread itself out. But the foot of the valley still consists of lake-loess. It is not fit for agriculture and sometimes becomes a large uninhabited salt field. In such places (and they are very numerous) an impure kitchen salt or natron, or soda is gained from the soil. Such places are very instructive when, as sometimes happens, in former times in consequence of temporary shrinking of the lake and the depression of its surface a quantity of land loess has settled down upon the lake loess on the zone which was quitted by the water. We can observe this connexion of the two kinds of loess with great distinctness in the valley of the Wei river in Shensi above and below Si-ngan-fu. This valley is rich in instructive explanations for the knowledge of the lake loess. DIAGRAM SHOWING THE DEPOSITION OF THE LAKE LOESS THROUGH ACCUMULA

TIONS OF LAND LOESS IN THE VALLEY OF THE WET RIVER IN SHENSI.

5

1. Lake loess. 2. Land loess. 3. Alluvium of the Wei. 4. Position of springs

very abundant in water. 5. Terrace on which stand several cities, such as, Si. ngan-fu, Hwacheu, etc.

The lake which once spread itself out here, was of great circumference and reached to the steep granite range of the sacred Hwashan mountain. The latter raises itself with its fantastically formed summits like a gigantic pillar on the outer angle of the knee bend of the Hwang-ho, while on the inner angle of the corner ascends the mountain known as Fung-tlau-shan, which was separated from the opposite range by a violent earthquake, if we are to believe the Chinese legend.

From both of them were washed down during periods of heavy rainfall masses of rubbish which had collected in ravines as rounded rubble, reaching the lake in that form. Therefore it is that layers of rough rubble, gravel and sand interchange here with extraordinarily fine hardened loess myud; while this hardened mud is found pure, and almost unaccompanied by gravel and stones, in other lakes distant from mountains. It is to be expected that the lake loess should be rich in lime, since in the land loess a proportion of 20 to 30 per cent of carbonate of lime is nothing rare. The proportion of it collected in the salt lakes is in far greater quantity and by evaporation always takes its place as a deposit sooner than that of the land loess. In fact it not only causes the white yellowish colour of the fine earthen lake loess, but also cements together sand, gravel and an earth resembling fish roe, and is besides this formed into concretions, mostly very small, their size varying from that of peas to that of nuts. They collect sometimes in extraordinary quantities and may then easily be mistaken for lime-túfa. All these formations lie open to view on the fortified pass of Tung kwan and from thence to a point far above Si-ngan-fu,' to the natural walls which enclose the alluvial valley. On the large terraces which are made by the above-mentioned formations lie numerous towns of great size, among which is the old capital Si-ngan-fu itself. Above it on both sides of the river ascends the land-loess which has quite plainly been deposited on the stratified formation, and gives the proof that after the period of the greatest enlargement of the lake, another drier time followed in which the lake withdrew and the dry steppe land gained more and more expansion over the region once occupied by the water of the lake. On the strip of plain which separates both formations many springs are found. The difference in regard to penetrability by water in the two formations is here to be seen very distinctly.

With the proof of the salt lake deposition on the ground of the loess trough, disappears the last doubt which could have arisen against the conclusion, that the latter are to be considered as former salt steppe basins. We may affirm with certainty that the North of China was in former times when the Yellow River did not yet exist, a steppe land which resembled in every way the neigbouring regions belonging to the present Central Asia. North China consisted of single basins (without outlet for water) of very different sizes. In these, rivers discharged themselves into salt lakes where the water evaporated. The evaporation was greater than the precipitation, or equal to it, and a continental climate reigned. The immensity of the slowly growing loess offers a measure by which we can get an idea of the long duration of this period, since we have no data for obtaining a more definite estimate of it. In the south the mountains known as the Tsing-ling-shan formed a sharper boundary to the plateau of that time, than now exists probably to the steppe lands of Central Asia in any one direction, since on the other side of this range there is not found even so much as a trace of loess. But its eastern part, the Fu-niu-shan, stretches into the steppes in a similar way to the eastern outlying branch of the Tiën-shan in Chinese Turkestan.

As to the causes of the great difference between the former state of the climate and the present, only conjectures can be made. One of them might be found in the fact that the mainland of Asia was at that time raised higher in its eastern part than at present and stretched further eastward into the sea, as I shall endeavour to show in another chapter. Therefore maritime influences came from a greater distance and the dampness of the south winds was caught and appropriated by a greater mass of mountains. In the relatively slow sinking of the land and the approach of the sea might be found partly the cause of the change by which countries without an outflow came to have a drainage. This process, we can only explain by stating that at first one basin was formed, then another, and so on, beginning from the east and going towards the west, and that by x very minute increase of the precipitation each slowly attained the the

power of creating thus a drainage for its waters. In some places a union of several basins might have taken place before the outflow in the direction of the present streams began. As soon as it was once created and the canal so deep dug, that it stood as to height at most on the same level with the bottom of the central water basin, there must, if no great change in the climate took place, be a permanent drainage, and the river system must develop itself more and more to completeness. In consequence of the particular way in which the single basins were arranged it happened that with the exception of the eastern parts of the continent one channel became the principal medium for drainage. It was the Hwang-ho or Yellow River of to-day. More and more lake basins were drawn into it and it grew slowly till its area of drainage reached its present expansion, and probably it is still encroaching gradually on the undrained plateau. The change is a mighty one, but not necessarily permanent. Even in case of a great diminution of the rainfall in the North of China, the Yellow River would continue to flow, and receive the tributary waters of its affluents, however much smaller that tribute might be. But besides the diminution of the rain other circumstances might occur which would be sufficient to lead matters back to their former condition. I will in the next chapter try to represent the circumstances which make it possible that through climatic changes a district having a well ramified system of streams can be changed into a salt steppe land without outward drainage.

If the North of China were still in its former state, it would be unsuitable for agriculture, with exception perhaps of a few irrigated oases like those that are found in the region lying south of the Tiënshan range of mountains. Nomades would inhabit them. The change of the salt steppes into loess countries was an infinite blessing. The salt of those parts which were situated above the level of the rivers was washed out, and the soil, which before was only suitable for steppe-vegetation, became fruitful and productive. In the wide bottoms along the banks of rivers, especially in localities where on both sides the former soft surface earth of the steppe troughs is still preserved, as in the great valley of Si-ngan-fu, opportunity was offered for the settlement of a numerous population, and for the blossoming of a culture such as nomades cannot create. By it the soil was here prepared for the Chinese, where they planted the germ of their future greatness and historical importance. They followed the stream downwards and took possession of the Great Plain, formed by the Yellow River from the loess which it had carried with it from its upper course. This is a second element of happy result which attended the change of the steppe land into the district watered by the Hwang-ho, and its tributary streams.

Thus the geological study of the loess countries in the North of China allows a far view to be gained into the primitive history of eastern Asia, into the conditions under the limiting control of which the development of its inhabitants and their culture proceeded, and into the real nature of the central portions of the continent. The question follows close and claims discussion whether such changes as the loess points out to us, have taken place only in the North of China, and not in larger expansions of territory around the present Central Asia. It is evident that the answer would contribute much to the geographical and historical understanding of the whole continent. To this question which I shall discuss in another chapter I will reply now only by giving in advance an introductory view of the events which create steppes without drainage and those which cause transformations to take place in them in different respects. This I shall do in order to lay a foundation so that we may then be able after learning the present character of the surface of many tracts of country to draw conclusions as to the processes which were formerly in operation in those regions and on their causes.

NOTES ON THE HISTORY OF SUCHOW.

By Rey. A. P. PARKER.

THIS so-called “ History” is a bulky work of 150 volumes of over fifty

pages each. I have read and noted parts of it which may perhaps be of interest to the readers of the Recorder. I shall not attempt a consecutive history of the city, but will notice only a few of the more prominent points of interest that I have been able to glean from

THE BOOK.

This gives, in unconnected portions, the principal facts (and fancies too) in relation to the men and things that for more than two milleniums have played their parts in unceasing succession in the history of this great city. There is no attempt made at giving the history of Suchow in this work. It is simply a collection of records and annals-in a word the archives of Suchow.

The first two volumes contain a record of the visits of several emperors to the city, and their sayings and doings while here, together with various Imperial Autographs that had been bestowed upon men whom the emperor had met, or places he had visited.

Not until the fourth volume is reached is any record found of the time when the city began to be, and then only in a very meagre and unsatisfactory manner is the record made. It is only here and there as one wades through this great mass of tedious details that the principal facts of the history are found.

These annals are the work of many hands. According to the preface, the first topographical history of Suchow was written in the Sung dynasty, about A.D. 900, by Fan Wên Kung (FU * 2), a name held in great reverence by the people of this city and surrounding country. His grave is situated about six miles west of the city and is visited every year on the 11th day of the 3rd moon by many people, who go there to burn incense, and pay respect to the illustrious dead.

« AnkstesnisTęsti »