OBSERVATIONS IN CENTRAL SHAN-SI. 173 
the older formations should become prominent, the forms would, in all probability, have the 
character of a disturbed mountain range, but after an interruption the lines of height become 
flat again and show the plateau structure which we had previously observed.* 
In explanation of the apparently abrupt occurrence of the jagged 
mountain range, in the otherwise flat-topped plateau, von Richthofen 
infers an extension of the normal fault which he had observed 100 miles, 
160 kilometers, further southwest, on the western side of the Fén-ho at 
the foot of the O-shan.t 
Obrutschov{ observed the same mountain range and gives the annexed 
diagram of its structure. He does not appear to find any ground for the 
existence of the normal fault inferred by von Richthofen, but accounts for 
the flattening of the mountain profiles toward the west by the horizontal 
attitude of the limestones on the summit of the arch. A translation of his 
explanation follows. 
The road (leaving Yung-an-chén) leads toward west-southwest. At the north the 
cross profile of the Tsan-hua-shan ridge is very well shown, and the strata appear to and 
indeed do constitute a flexure. On 
the eastern slope they dip toward the 
east or east-northeast at an angle of 
Nr S 50° or 60°; near the crest of the ridge 
/ WN they bend over, and in their upper- 
AM most bed they lie generally horizon- 
Fic. 53 (Obrutschov).—Wo6n-shui-hién, Shan-si. Diagrammatic tally, forming nearly flat folds ; the 
section of Shi-hia-shan after Obrutschov. more western beds dip very steeply 
westward, forming also flat folds of 
second grade (Fig. 53). The conditions of stratification can be especially well examined 
from the thickness of the dark, thick strata, probably Carboniferous limestone, which 
form vertical gorges on the upper part of the steep southern (probably downthrown) 
flank of the ridge; below these strata the mass of the ridge is probably made up in part 
of Sinian limestone, and below them of crystalline rocks which may be stratified. 



RA 
We did not observe the occurrence of rocks below the Sinian system, 
but we inferred from the general dip of the limestones that such rocks 
must form the mass of the mountains west of the range. This inference 
*China, vol. u, p. 432. ‘‘Denn an dem Weg nach dem grossen, in fruchtbarer Gegend gelegenen 
Wonn-shui-hsien sieht man den Plateau-abfall von einem zackigen, wenigstens zu 2500 Fuss tiber der 
Ebene aufsteigenden Gebirge, dem Shi-hsia-shan, tiberragt. Bald gewinnt man die volle Ansicht von 
Siiden. In scharfem Contrast erblickt man neben dem horizontalen Schichtenaufbau der buntgefarbten 
Plateaugebilde ein machtiges System dunkel erscheineder Kalke, die aber durch gelbe Schichtenabbriiche 
ihre wirkliche Farbe verrathen, in steiler Stellung aus dem Thal aufsteigen. Man ist geneigt, dies fiir 
ein weit Alteres Schichtgebirge zu halten. Allein der weitere Verfolg rechtfertigt diese Vermuthung 
nicht. Der von Nordost nach Stidwest gerichtete Gebirgsabfall ist zu Ende. In einer weiten Bucht 
erstreckt sich die Ebene nach Westen hin. Da die Strasse quer tiber die Bucht fiihrt, so konnte ich nur 
aus der Ferne die Formen des Gebirgsabfalls in seinem westlichen Verlauf erblicken. Wenn die Alteren 
Formationen hier herrschend wiirden, so miissten die Formen mit grésster Wahrscheinlichkeit den Char- 
akter von gestértem Gebirge tragen. Allein nach der einen Unterbrechung verflachen sich die Héhen- 
linien wieder und zeigen denselben Plateau-Bau an, wie wir ihn bisher sahen ”’ 
{ China, vol. u, p. 421. 
{Central Asia and Northern China, 189-294, p. 171. 
