60 Perner & Kodym — Zonal Division and 



Kozel). This zone yielded: Monograptus testis Barr., 

 M. bohemicus Barr., M. flemingi Salt., M. nilssoni Barr., 

 M. dubius Suess, Cyrtograptus lundgreni Tullb., and 

 Retiolites (Gotliograptus) nassa Holm. In addition have 

 been f onnd associated : Ampyx rouaulti Barr., Palman- 

 ites orba Barr., Proetus (Phcetonellus) dentatulus Novak, 

 Piscina unguis Barr., P. nana Barr., Orthis honorata 

 Barr., and Orthotheca fragilis Nov. 



b. Zone with Monograptus colonus Barrande. — Lith- 

 ological character nearly the same, brown, somewhat 

 argillaceous shales prevailing, concretions frequent; the 

 alternating limestones here more frequent, dark, non- 

 crystalline, compact (in contrast to the majority of the 

 very similar E 2 limestones), sometimes with numerous 

 cephalopods or crinoid fragments. Associated occur 

 here : Monograptus colonus Barr., M. nilssoni Barr., M. 

 bohemicus Barr., M. roemeri Barr., M. goilandicus Per., 

 and M. unguiferus Per. In the same zone, the concretions 

 and limestones yield, sometimes in association with the 

 graptolites named above: Cyrtoceras vestitum, Gompho- 

 ceras clava, Ophidioceras proximum, Orthoceras epulans, 

 0. socium, 0. illudens, 0. pleurotomum, 0. styloideum, 

 Ascoceras cf. murchisoni, Cirropsis spp., Cyrtolites 

 eximius, Euryzone tuboides, Orthonychia ampla, 0. ele- 

 gans, Platyceras longipes, Polytropis (Poleumita) potens, 

 Spirina paiida, S. tubicina, Avicula glabra, Slava 

 bohemica, Cromus beaumonti, Cyphaspis, and Plcenus 

 bouchardi. The shales of Ejy also sometimes contain 

 Orthoceras, some Acephala, and brachiopods, but these 

 are mostly undeterminable. 



Reef-facies in Barrande ? s Etage E. 



The upper Ej beds in the northwestern Silurian region 

 are developed as coral-reef fades, with coarse crystalline 

 limestones of gray or brown color (never white as in F 2 ), 

 sometimes indistinctly stratified, or nodular. The lowest 

 part of these limestones must be attributed to E 2 beds, as 

 their base is formed by the zone of Cyrtograptus murchi- 

 soni (Ej/?). They extend up from E x y to the highest E 2 

 beds, and it is most probable that they existed in some 

 localities without a noteworthy interruption until the mid- 

 dle part of Barrande's Bande G u which is of Lower 

 Devonian age. 



