34 GEOLOGICAL RESEARCHES IN 



course of these excavations, fossil remains of quadrupeds are obtained in consider- 

 able numbers, especially horns of deer.^ 



Leaving Siwan the road lies first southeast, then south, crossing two ridges ■ of 

 chloritic gneiss and chloritic schist, and descending into the large oval valley of 

 Chauchuen. This valley is occupied by the terrace deposit. Our road ascends the 

 ridge forming the southern side of the vaUey. On the northern flank are the crys- 

 talline metamorphic schists covered by limestone, and over this beds of porphyry 

 breccia with dykes of eurite. The terrace deposit rises almost to the summit of 

 this ridge on both sides. Descending through the deep gullies in the terrace 

 loam, the road enters the valley of a creek that empties into the Yang Ho, just north 

 of the Kiming mountain. From this valley we cross the ridge, by a low pass east 

 of the Kiming mountain, into the valley of the Yang Ho, and descend to Sinpauflgan. 

 The low pass is covered by the terrace deposit, and beneath this on the northern 

 flank are the coal rocks of the Kiming field, among which I saw a greenstone por- 

 phyry conglomerate similar to that at Hiangshui (pu), and probably its equivalent. 



The terrace deposit in the pass consists of loam with gravel and fragments of the 

 neighboring rocks, and occupies a higher level than the terraces of the valley to 

 the south. 



I will now attempt a general description of the principal rocks met with on the 

 above journey. I am well aware that the following description can have but a very 

 limited value, owing to the absence both of chemical determinations and of closer 

 observations of the modes of occurrence. 



Granitic and Crystalline Metamorpldc Series. 



Distribution. — These two classes of rocks form either collectively or individually 

 the main body of every ridge we have traversed. Of them consist the ridges that 

 rise through and above the volcanic mantle of the plateau, and they form the 

 foundation on which this rests wherever the foundation was seen. Indeed, they 

 are the skeleton of this region, supporting the limestone floor of the coal rocks. 



Granite predominates in the first range where we crossed it in the Nankau pass ; 

 in the other localities, if it exist, it is covered by the crystalline schists. 



Unstratified Granitic Roclis. — The main body of the ridge between Nankau and 

 Chatau consists of a granite containing two varieties of feldspar, about equally dis- 

 tributed in crystals varying from an eighth of an inch to three-quarters in length. 

 These are pink orthoclase and a white triclinic feldspar. The mica is a dark green 

 almost black, probably magnesian variety, and quartz is present in comparatively 

 smaU quantity. It is thus a granitite. 



Near the middle of the pass is another variety, of even grain, consisting of only 

 white orthoclase and gray quartz, the latter often in sharply-defined, small prismatic 

 crystals imbedded in the mass. It is somewhat remarkable from small cells in which 



* As all the fossils of any value had been sent to Paris previous to my visit, I vpas unable to obtain 

 any that were worth examining. It is to be desired that those now in Paris will be determined and 

 described in order to fix the ac-e of the terrace formation. 



