NO. I CAMBRIAN FAUNAS OF EASTERN ASIA 63 



■ took place at the close of the Man-t'o shale epoch. Willis concludes 

 that aridity and severe cold were conditions of the climate during 

 Man-t'o shale time ; that life was abundant elsewhere and with the 

 changing climate it developed rapidly in the seas following the Man- 

 t'o.^ Of the rocks of the Kiu-lung group following the Man-t'o, 

 he says : 



Middle Sinian, Kin-lung group. — The Kiu-lung group of Shan-tung is a 

 succession of limestones and shales which immediately follows the Man-t'o 

 formation. Transition beds connect the two. Shale is a common rock in 

 both, but in the Man-t'o it is red, whereas in the Kiu-lung it is green. Lime- 

 stone is thin-bedded and subordinate in the former, in the latter it is usually 

 massive and predominant. The Man-t'o contains a sparse Middle or Lower 

 Cambrian fauna in its upper portion; the Kiu-lung carries very abundant 

 faunas, which range from Middle Cambrian at the base to Upper Cambrian 

 and possibly to lowest Ordovician at the top. 



The known distribution of the limestones and shales and their 

 contained faunas of the Middle Cambrian is outlined by Willis, also 

 the area in which they are supposed to occur." The known distribu- 

 tion from Manchuria on the northeast to central China, and west 

 into northern India,^ taken with the occurrence of fragments of the 

 fauna in Siberia in the valleys of the Lena, Yenisei, and Angara," 

 indicates something of the extent of the Middle Cambrian sea. The 

 larger area outlined by Willis in which Cambrian rocks are supposed 

 to occur is probably much too small, as later rocks undoubtedly con- 

 ceal large areas of the Cambrian. 



The prevalence of limestones with interbedded calcareous and 

 argillaceous shales indicates relatively shallow seas and favorable 

 environment for the life of the sea. This inference is supported 

 by the number of genera and species already found in the hurried 

 collecting necessitated by the conditions of exploration met with by 

 the Willis and Iddings parties. 



In the Ch'ang-hia District the Middle Cambrian is represented in 

 the Ch'ang-hia limestone, in the Sin-t'ai district by the lower portion 

 of the Kiu-lung limestone, and in Shan-si by the lower 400 feet 

 (118 m.) of the Ki-chou limestone. 



^ Willis, Bailey. Research in China, Pub. No. 54, Carnegie Institution of 

 Washington, Vol. 2, 1907, Systematic geology, p. 40. 



^ Idem, pi. 4. 



^ Reed, F. R. C. Mem. Geol. Survey India, Palseontologia Indica, ser. 15, 

 Vol. 7, 1910, No. I, The Cambrian fossils of Spiti, p. 66. 



* Toll, E. von. Mem. 1' Acad. imp. Sci. St. Petersbourg, 8th ser.. Vol. 8, No. 

 10, 1899, Beitrage zur Kentniss des sibirischen Cambrium, pp. 1-57, pis. 1-8, 

 and 9 text figs. 



