56 Perner & Kodym — Zonal Division and 



Retiolites geinitzianus in some localities without nodules 

 and limestone intercalations; in others, however, they 

 are crowded with them, although they both correspond to 

 Marr's "priodon zone." The same thing occurs in some 

 upper zones. The division into three parts is, I am con- 

 vinced, more appropriate to the three distinct graptolitic 

 faunas existing in Ej and in general fits to the facts known 

 from other countries. 



E x a — Diplograptus Beds. 



Eja or the Diplograptus beds is characterized by the 

 frequent occurrence of many species of Diplograptus and 

 other genera of the Diprionidse, which are all absent in 

 the upper beds. It contains four zones, as follows : 



a. Zone of Diplograptus vesiculosus Nich. — Soft, 

 light yellow or brown, lilac-shaded shales, known only from 

 Belec* and Libomysl. Aside from D. vesiculosus and an 

 undeterminable Climacograptus , no other graptolites are 

 known from this zone, demonstrating that in Bohemia, 

 beds of Lower Llandovery age are also represented. In 

 the other localities this zone can not be ascertained, as for 

 instance, in the vicinity of Tman, where similar shales 

 resting directly on D 5 (Ordovician) have so far yielded 

 no graptolites. At Korno and elsewhere black shales 

 lying on D 5 are metamorphosed by diabase intru- 

 sions into hard hornstone-like shales without a trace of 

 graptolites. At several localities this zone is certainly 

 absent (for instance, at Zadni Treban), because the black 

 shales lying directly on D 5 belong already to the next 

 higher zone (Rastrites peregrinus). It seems that the 

 transgression which began after the close of Ordovician 

 time gradually reached different places in the ' ' Silurian 

 basin" of Barrande. 



b. Zone of Rastrites peregrinus Barr. — This zone also 

 contains shales but of different petrographical characters, 

 and is developed in the entire area of the Silurian. For 

 example, at Treban, Motoly,and colony "Haidinger" 9 

 between Radotin and Kuchelbad, the zone consists chiefly 

 of soft micaceous, somewhat arenaceous, black or gray 

 shales ; in the vicinity of Tman, of yellow or grayish, lilac- 



* In this and other cases beyond, the accent is from necessity omitted. 

 9 The names of Barrande ? s colonies are used here only as designations of 

 localities. 



