FAUNA OF THE KI-SIN-LING LIMESTONE. 293 



America, although it is apparently an immigrant in our faunas. The Chinese 

 species T. poloi, however, is of the typical American form of the genus, being 

 more or less remotely related to T. extans Emmrich of the Trenton limestone. 

 The range of the genus in North American faunas is from the lower Ordo- 

 vician or Canadian to the Niagaran division of the vSilurian. Plec tor this is 

 a widespread genus in the Ordovician faunas of both North America and 

 Europe. Clitambonites occurs rarely in the middle Ordovician or Mohawkian 

 faunas of North America and more commonly in the European faunas, its 

 relationships are European rather than American, and Hemipronites is strictly 

 a European genus. Both of these two last genera have their greatest develop- 

 ment in the faunas of the Baltic provinces of Russia, where they occur in the 

 Glauconite and Vaginatus limestones associated with Orthis calligramiim. 

 The genus Strophomena, which occurs abundantly in the Chinese fauna, 

 although the species has not been identified, is a much more conspicuous 

 member of the North American Ordovician faunas than those of Europe, 

 although it is not uncommon in Europe. 



Among the trilobites the most conspicuous feature in the Chinese fauna 

 is the great variety of Asaphidae belonging to the genera Asaphns, Megalaspis, 

 and Isotelus. Another notable faunal character is the presence of the genus 

 Ampyx. Although none of the species of these genera of trilobites has been 

 certainly identified with previously known forms, the complexion of the whole 

 assemblage is strongly suggestive of the same Ordovician faunas of the Baltic 

 provinces of Russia that are characterized by the brachiopods Hemipronites, 

 Clitambonites, and Orthis calligratnma. The genus Isotelus is conspicuous in 

 the North American faunas, but Asaplnis proper and Megalaspis do not occur. 

 Among the Chinese species Asaphus blackivelderi and the pygidia compared 

 with Asaphits ex pans us Dalman are of first importance. In Russia Asaplnis 

 expansus, which is certainly a close ally of these Chinese forms, is particularly 

 characteristic of the Glauconite limestone, and it occurs also in Scandinavia 

 at a similar horizon. The species here described as A in pyx ch incus is is closely 

 allied to .4 . nasittns Dalman, which occurs in both the Glauconite and Vaginal us 

 limestones of the Baltic provinces of Russia and in limestones of similar age 

 in Scandinavia. Ampyx costatns Boeck, with which one of the Chinese 

 species is compared, occurs in the Echinospheerites limestone of the Baltic 

 provinces, the formation superjacent to the Vaginatus limestone. 



The single form of cephalopod from the Ki-sin-ling limestone has been 

 referred to the genus Vaginoceras. In America the described species of this 

 genus occur in the Black River limestone. In the Baltic provinces of Russia 

 the genus is represented by the Orthoceras raginatuni, whose great abundance 

 has given name to one of the Ordovician formations of that region, the Vagin- 

 atus limestone, sometimes also called the Orthoceras limestone. 



The above analysis of the Chinese fauna described in this paper shows 

 clearly its strong relationship with the north European Ordovician faunas, 

 and especially with the fauna of the Glauconite and Vaginoceras limestones 



