RAYMOND: CORRELATION OF THE ORDOVICIAN STRATA. 



219 



Scania, while others are developed in both regions, 

 amplification of one given by Moberg (75). 



The table is an 



I 



Trinucleus or 

 Upper Dicellograptus shales 



Chasmops or 

 Middle Dicellograptus 

 shales (with limestone) 



Lower Dicellograptus shales 



Upper Didymograptus shales 

 Orthoceras limestone 



Lower Didymograptus shales \ 



Ceratopyge limestone 

 Shumardia shale 

 Dictvonema shale 



Zone of Phacops cucentra and Stauro- 



cephalus clavifrons. 

 Zone of Aviypx portlocki. 



Zone of Pleurograptus linearis. 

 Zone of Calymene dilatata and Dicra- 



nograpUis clingani. 

 Zone of Nemagraptus gracilis. 

 Zone of Climacograptus pidillus. 

 Zone of Glossograptus kincksi. 



Zone of Didymograptus geminus. 

 Zone of Phyllograptus cf. typus. 



Zone of Isograptus gihherulus. 

 Zone of Phyllograptus an gustif alius. 

 Zone of Didymograptus balticus. 

 . Zone of Tetragraptus phyllograptoides. 



The fauna of the Trinucleus beds has been described by Olin (79), 

 who enujnerates many species. Of trilobites forty-three species were 

 listed, and it is of particular interest to note that twelve of these are 

 species common to Sweden and Bohemia. Prominent among such 

 species are Cheirurus pedinifer Barrande, Remoplcurides radians Barr., 

 Calymene incerta Barr., C. pulchra Beyr., PhiUipsia parabola Barr., 

 " Asaph us" ingens Barr., Trinucleus hucklandi Barr., Ampy.v gratus 

 Barr., A. portlocki Barr., A. tenellus Barr., and Aeglina rediviva Barr. 

 In addition to these common species, the genera Aeria, Staurocephalus, 

 and Dionide in themselves suggest the Bohemian fauna. Other 

 important species in the fauna are Phacops (Dcdmanitcs) cucentra Ang., 

 Agnosias trinodus Salter, and Stygina latifrons Portlock. The im- 

 portant graptolites are Dicellograptus complanatus Lapw., and Diplo- 

 grapfus truncatus Lapw. 



The Chasmops beds contain a rather small fauna, but although 

 there are many limestone bands in the shales, there are fewer trilo- 

 bites and more graptolites. Olin lists among others Calymene dilatata 



