24 BULLETIN 164, UNITED STATES NATIONAL MUSEUM 



Canadian 



SaNTAO FORMATION : 



Moderately thick-bedded, jirayish dark, somewhat arenaceous lime- 

 stone, the beds averaging 3 cm in thickness, GO m (196.8 feet). 



Fauna. — Hormotoma sp. and Calathiuni frechi., new species. 



The Santao is found on the western slope of the curved ridge west 

 of the Hui-kou Valley and on the eastern slope of Wu-ting hill. 



PENHSIHU-NIUHSINTAI SUBDISTRICT 



This area extends from Chiao-tou station, on the Antung-Mukden 

 line, to Huo-lien-chai station, thus including a strip about 8 miles 

 wide lying both east and west of the railway line. In this area the 

 Ordovician and Canadian strata outcrop sporadically north of the 

 Pen-hsi-hu colliery, in the vicinity of the Tao-yuan-kou colliery, in 

 the country around the Niu-hsin-tai colliery, on Fu-chin-kou 

 ridge, 2.5 miles southwest of Miyanohara station, and at other places. 

 (Pis. 8, 9.) 



The black-banded limestone of the Ssuyen forms a great cliff near 

 Ssu-yen-kou, just north of the Pen-hsi-hu colliery, where it yields 

 many fine fossils. 



The Santao formation is typically developed above the second tun- 

 nel, 1 mile north of the Pen-hsi-hu colliery, and here are found many 

 fine characteristic Canadian fossils (pi. 5). 



FU-CHIN-LING SECTION 



The Ordovician and Canadian strata outcrop fairly extensively in 

 the westward i^rolongation of the Cambro-Ozarkian outcrops 1.5 

 miles north of Chiao-tou station and near Po-chia-wan, 3 miles 

 southwest of Miyanohara station. 



The strata from the Ordovician Wuting to the Ozarkian Yenchou 

 form an anticlinal structure, while the Ssuyen is shifted out to the 

 northward of this section by a large fault ; here it is in contact with 

 the strata from the Ordovician Wuting down to the Sinian Tiaoyu- 

 tai in the area from Po-chia-wan via Fu-chin-kou to Yao-kou-pu. 



Ordovician 

 Ssuyen formation : 



Moderately thick-bedded, gray to black limestone with many calcite 

 veins, with occasional intercalated dolomitic limestone beds at ir- 

 regular intervals. 



Fauna. — A good fossil locality of this formation is located on 

 the northern slope of the Fu-chin-kou ridge, where I collected the 

 following fossils : 



