Vol I. Graban Ordovician Fossils from North China (i) 11 



commonly in the Lower Cambrian. One species however A. minganense Bill, has been 

 obtained from the Lower Ordovician of the Mingan Islands eastern Canada. This species 

 has no inner wall and has been made by Hinde the type of his new genus Archssowyphia, 

 Our species is of the same generic type. The occurrence of this fossil, which appears to be 

 fairly common, is sufficient indication that the Peilintxe limestone represents lowest 

 Ordovician. The presence of a Protocameroceras very similar to P. brainardi of the 

 American Beekmantown, further indicates the correctness of this classification, as does 

 nlso the presence of Ophileta. Chihlioceras represents a new type of cephalopod and for 

 it the new family of the Ckihlioceratidx is erected. Its nearest relation is Piloceras, but it 

 is very distinct from this in its siphuncular structure, which, curiously enough, is much 

 more specialized and complicated than is that of Piloceras. The presence in this fauna of 

 the species of the latter genus, characteristic of the higher formation, is open to some 

 doubt, as it is possible that there may have been a mislabeling of specimens in the field. 

 If it really belongs here, it is the only species which the two divisions have in common. 



The base of the Peilintze limestone has not yet been found, and its relationship 

 to the older horizons is therefore unknown. All of the material here described comes 

 from the lowest fossiliferous horizon (F 1) except one fragment which contains several 

 specimens of Ophileta apparently of the same species as that in the lower horizon, though 

 the material is rather imperfectly preserved. This comes from F 2. 



LIANCHIASHAN LIMESTONE. No fossils have been obtained from the intermediate 

 shales and limestone of the Shihmunchai formation. The upper or Lianchiashan limestones 

 carry a fossil horizon (F 3) 223 meters above the base. At this level the following 

 species occur. 



GASTROPODA CEPHALOPODA 



1 Ophileta plana Grabau 3 Cameroceras styliforme Grabau 



2 Hormotoma doquieri Grabau 4 Piloceras platyventmm Grabau 



This is a small but distinctive fauna, and one confined to this horizon unless the 

 presence of Piloceras platyventmm in the lower beds should be substantiated. Both the 

 Piloceras and the Ophileta indicate Lower Ordovician, or a horizon approximate- by 

 equivalent to the upper Beekmantown of North America. Hormotoma indicates a some- 

 what higher horizon and the fauna may perhaps represent early .Middle Ordovician, but 

 can scarcely be higher so far as the known species permit us to judge. 



The relationship of these faunas to the Ordovician faunas of the Kaiping basin 

 farther south, is still obscure. The beds which there rest disconformably upon the Upper 

 Cambrian have so far furnished few fossils only, all of which are entirely unknown in 

 either of the two horizons in the Shih-mun-chai region. Further search may of course 



