42 RESEARCH IN CHINA. 



fossil content in both, confirms this. Characters common to shoal-water 

 deposits mark these beds, which, though most frequent in the middle of the 

 Kiu-lung group, occur also in the underlying Man-t'o. The conditions of 

 occurrence, the constitution, and the detail of the conglomeratic layers 

 require that during the deposition of calcareous mud in shallow waters there 

 shall have been some layers that hardened more or less firmly to limestone 

 strata. There is no evidence that they were extensive or continuous; they 

 may probably have been limited and separate; but they were common. 

 The mud containing these layers was disturbed and the more or less con- 

 solidated lime rock was broken, washed, and redeposited, after the manner 

 of a conglomerate. A portion of the process as yet eludes interpretation. 

 We do not know the physico-chemical or organic conditions under which 

 limestones consolidate, and are therefore at a loss to understand why some 

 layers or nodules harden before others. Our speculations are given in vol- 

 ume I, part ii. 



The upper part of the Kiu-lung group is a thick-bedded uniform lime- 

 stone, of light-blue to gray color and usually smooth texture. From its 

 development near the village of Ch'au-mi-tien in the Ch'ang-hia district, 

 we called it the Ch'au-mi-tien limestone. Its thickness is about 580 feet, 

 175 meters, in the type locality, where it directly overlies the Ku-shan 

 shale. In Kiu-lung hills the rock occupies a similar stratigraphic horizon 

 and carries the Upper Cambrian fossils, which characterize it in the type 

 locality, but its limits are not so clearly defined. In marked contrast to 

 other Sinian strata below it, the Ch'au-mi-tien limestone is horizontally 

 continuous and uniform. It represents a wide-spread condition of deposi- 

 tion, such as the circulation of a broad marine current over a continental 

 shelf, and thus differs from the strictly littoral aspects of the Man-t'o 

 terrane, and the inconstant phases of the shaly part of the Kiu-lung 

 division. 



Upper Sinian. The Tsi-nan limestone, so named after the capital 

 city near which it is exposed, is the highest formation of the Sinian system 

 in Shan-tung. It differs from the underlying Ch'au-mi-tien, being less 

 plainly stratified, dark gray to brownish in color, and poor in fossils, which 

 are of lower Ordovician types. It may commonly be divided into two 

 members : a lower, 250 feet, 75 meters, thick, consisting of shale and coarse 

 crystalline dolomite, which weathers like calcareous sandstone; and an 

 upper, 2,500 feet, 750 meters, or more, which is dolomitic limestone. The 

 total thickness is indeterminate, since the upper surface is one of erosion, 

 even where it is covered by later sediments. 



This Ordovician limestone was confused by von Richthofen, who found 

 no fossils in it, with the very similar Carboniferous formation that he had 



