MIDDLE PALEOZOIC, SHEN-SI. 57 



(t) Beds of limestone which contain much clay shale ; the limestone consists almost 

 entirely of corals in distinct, very well-preserved individuals, which attain more than one 

 foot in diameter and are separated by shaly material. Favosites jorbesi, Haly sites catenu- 

 larius, several kinds of Heliolites, Cyathophyllum,Amplexus, and Aheolites occur, according 

 to the determination of Lindstrom, together with other Silurian forms. Crinoids are 

 numerous, brachiopods and Orthoceras scarce. Of trilobites I did not find any. 



(h) Green clay shales, which are distinguished by occasional layers full of nodules of 

 limestone in bedded form. When weathered these are recognized as the remains of corals, 

 which belong to some of the species enumerated in i, but are much smaller. Limestone 

 layers of the most varied character and coloring are interbedded with the shales and 

 alternate with them, now in thick beds, again in the thinnest layers. The number of 

 fossils is extraordinarily great in this easily recognized formation. Every calcareous piece 

 exhibits organic structure. Together with the corals occur innumerable long crinoid 

 stems, small trilobites, and many brachiopods, especially species of Orthis. The last 

 occur in such heaps that they alone constitute single limestone beds. According to the 

 determination of Dr. Kayser, the terranes i and h are Upper Silurian, approximately 

 equivalent to the Wenlock. 



(g) Gray limestone and soft gray calcareous marl, which, according to the occurrence 

 of Airy pa reticularis, is Devonian. 



(/) Strongly bituminous limestone of blackish and liver-brown color, which is without 

 question identical with the Carboniferous limestone. 



The gray, splintery limestone at the base of this section is not recog- 

 nized by von Richthofen as representing the Sinian, but probably is of the 

 transition beds, which follow the typical limestone of that system on the 

 Ta-ning-ho. As von Richthofen had not distinguished the Sinian from 

 the Carboniferous, he was not prepared to recognize it where only the top 

 appears in an unfamiliar stratum. 



The lydite conglomerate corresponds with the black chert bed which 

 occupies a similar horizon in the Ta-ning-ho section, and the fauna collected 

 by von Richthofen from the beds / and k, and described by Kayser, is 

 regarded by Weller as closely related to that which we obtained at Su-kia-pa. 



In this connection it is desirable also to mention certain fossils 

 described by Martelli,* collected by the missionary Giuseppe Giraldi in 

 the vicinity of "Lean-san," in the Ts'in-ling mountains of southern Shan- 

 si, f I have not been able to find the locality "Lean-san" (which may 

 perhaps be transliterated L/iang-shan, Two Mountains) on any European 

 or Chinese map available, but it can not be far from the section observed 

 by von Richthofen. Weller regards the fauna collected by Father Giraldi 

 as even more nearly related to that from Sii-kia-pa than is that described 

 by Kayser. 



*Bol. Soc. Geol. Ital., vol. xx, p. 295, Fossili del Siluriano Inferiore dello Schensi (Cina), Alessandro 

 Martelli. 



t Probably the same as Abbe David's Lean-chan, described by Paul Fischer in Bull, de la Soc. Ge'ol., 

 Ser. m, vol. n, p. 408. 



