(i) 6 Palscordoloyia Sinica Ser. B 



and 58 species 45 of these being specifically identified.* All except five of the species are 

 new. Three new genera, and a new family of cephalopods, that of the Ckihlioceratidee arc 

 described. 



STRATIGRAPHIC SUMMARY. 



Willis and Blackwelder applied the name Tsinan formation to the entire 

 Ordovician series of North China, which they regarded as a unit. The name was taken 

 from Tsi-nan-fu in Shantung near which the upper beds of the series are well exposed. It 

 is now known that there are several Ordovician formations in north China, with probably 

 a disconformity between the higher and the lower divisions. The base of the Ordovician 

 has been definitely located in the vicinity of the little hamlet of Yehli, about 9 li or about 

 3.6 miles east-north-east of Machiakou in the Kaiping Coal Basin. Here the Ordovician 

 beds rest disconformably upon the Upper Cambrian or Cambro-Ordovician transition 

 beds, the Fengshan formation, which carries a fauna recalling the Ceratopyge fauna of 

 Europe, including a new species of Ceratopyge. The disconformity is marked by an 

 irregular erosion surface of the Fengshan formation followed by a basal conglomerate 

 which marks the beginning of the Ordovician limestones **). 



To the limestone immediately succeeding this basal conglomerate we 'have given 

 the name Yehli formation, and from it the following species have been obtained. 



CEPHALOPODA 



Suecoceras yehliense Grabau 

 Suecoceras attenuatum Grabau 



Extremely meager as this fauna is, it is sufficient to indicate early Ordovician, 

 but whether it is Lower or early Middle Ordovician must for the present remain undeter- 

 mined. The limestones of this region have a total thickness, according to the measure- 

 ments of Mr. H. C. T'an,- of approximately 800 meters, but whether this series is 

 continuous or separated into two divisions by a hiatus, has not yet been ascertained. 



UPPER ORDOVICIAN 



The upper beds of the Ordovician of the Kaiping basin are well exposed at 

 Machiakou, south-west of Yehli, and from this locality the formation is named the Machia- 

 kou division or Machiakou formation. This is the typical Actinoceras limestone, widely 

 exposed in the Kaiping basin from Chaokouchuang on the east to Tangshan on the west. 

 It is again known by fossils from the Western Hills of Peking, from the Sliansi border, 



*) This includes two varieties. Two others have been tentatively referred to known species. 

 *) This will be described by the author in the Bulletin of the Geological Survey. 



