Vol I. Qrabau — Ordovician Fossils from Nortli China (i) 11 



commonly in the Lower Cambrian. One species however A. mingnnense Bill, has heen 

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

 has no inner wall and has l>een made by Hinde the type of liis new genus Aa-h:roAcyp]iiii. 

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

 fairly common, is sufficient indication that tlie Peihntze limestone represents lowest 

 Ordovician. The presence of a Protocameroceras very similar to P. in-ainanli of the 

 American Beekmantown, furtlier indicates tlie correctness of this classification, as does 

 also the presence of Ophllcta. Gldhlioccms represents a now type of cejihalopod and for 

 it the new family of the ChiliUocerdtidir .is erected. Its nearest relation is Pilocems, 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. Tlie 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 mis]al)eling 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 LiJiESTONE. — No fossils havc been obtained from the intermediate 

 shales and limestone of the SJnhinunchdi formation. The upper or LiancJaasJian liimyfones 

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

 species occur. 



GASTROPODA CEPHALOPODA 



1 Ophileta plana Gmhan 3 Cavieroceras sfyJiforme Gyi\\>i\u 



2 Bormotovia doquieri Grabau 4 PiloceniA platyventrum Gi'abau 



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

 presence of Piloceras platyventrum in the lower Ijeds should be substantiated. Ik)th the 

 Piloceras and the Opliiletd indicate Lower Ordovician, or a horizon approximate! )y 

 equivalent to the npper Beekmantown of North America. Hormotoina indicates a some- 

 what higher horizon and the fauna may perhaps represent early jiiddle 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 Kaipiug basin 

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

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

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



