Correlation of the Silurian of Bohemia. 61 



A boundary between E x and E 2 can not easily be drawn 

 in these limestones, as their lithological character is the 

 same through the whole thickness of these deposits. 

 Graptolites are almost absent and the fauna bearing a 

 decided coral-reef character is for the greater part 

 unknown from the other "normal" parts of Ei or E 2 . 

 From the rich characteristic coral fauna, which occurs 

 chiefly at Kozel and Tachlovice, may be named : Holy sites 

 catenularia, Farosites asper, F. taclilovicensis, Cyatlw- 

 phyllum prosperum, Cystiphyllum bohemicum, and Om- 

 phyma grancle. Besides these corals, there frequently 

 occur in these deposits: Orthoceras caduceum, 0. endy- 

 mion, 0. pedum, 0. valens, 0. cur reus, Modiolopsis pupa, 

 Spanila cardiopsis, Cardiola persignata, Conocardium 

 dorsatum, Atrypa obolina, A. inelegans, A. reticularis, 

 A. squamma, A. dormitzeri, Bhynchonella niobe, R. 

 nympha, and R. princeps. The greater part of the Mol- 

 lusca and Brachiopoda mentioned above are apparently 

 confined to these coral limestones. 14 



In the immediate neighborhood of these coral reefs 

 there seems to be a peculiar trilobite fauna, represented 

 by Bronteus planus, Clieirurus insignis, Splice rexoclius 

 minis, Deiphon forbesi, Liclias, etc., the true horizon of 

 which belongs to E 1? as I have found them in the mud- 

 stones and limestones associated with Retiolites geinitzi- 

 anus, Cyrtograptus murcliisoni, Monograptus priodon, 

 and M. vomer inns. 



Baxde E 2 . 



As already stated, the boundary between E x and E 2 was 

 proposed by me on a paleontological basis, taking the 

 horizon characterized by Monograptus dubias, M. colonus 

 and M. roemeri as the highest in E x . As in E x , there are 

 to be distinguished in E 2 two different developments of 

 deposits or facies : (a) normal, stratified limestones with 

 intercalated shales and mudstones; (b) reef facies, with 

 nodular, indistinctly or irregularly stratified coral lime- 

 stones, a direct continuation of the reef facies mentioned 

 above in E T , and not divisible into zones, the faunal char- 

 acter remaining the same. 



14 Atrypa reticularis, Rhynchonella nymplia, and F. princeps occur also in 

 the coral limestones of the Devonian stage F 2 and extend to G,. 



