EOCKS OF BOHEMIA. . 597 



the uppermost grits of D d 5. Above these basement beds are 

 everywhere found the beds of Eel, capable of subdivision into 

 three horizons, characterized by differences of lithological character 

 and of their faunas, which are chiefly graptolitic. I shall treat of 

 the faunas when comparing the beds with their English equivalents. 

 The lowest of the three horizons consists of fine black mudstones, 

 divided by bedding and joints into small squarish prisms, and 

 sometimes into wafery shales. It contains also, in places, greenish 

 gritty beds an inch or two thick, as at Litohlav. The middle 

 horizon also consists of black mudstones, of a more flaggy character 

 than the last, and containing calcareous nodules and bands, usually 

 black also ; these are the Anthracolite spheroids of M. Barrande 

 (Def. des Col. iv. p. 26). 



The uppermost horizon consists of sandy and ferruginous shales, 

 weathering brownish yellow, containing calcareous nodules, and 

 passing into thin-bedded limestones, which compose the summit of 

 Eel. Between e 1 and e 2, in the valley of Tachlovice, is a band 

 of oolitic ironstone. 



E e 2. A greyish crystalline limestone, crowded with fossils, and 

 of nearly unvarying character. At one locality, however, near 

 Lodenice, it contains a yellowish ferruginous and calcareous shale. 

 The fauna is exceedingly instructive, and shows how careful we 

 should be not to conclude two deposits to be of different age, from 

 their possessing different faunas at short distances apart. In the 

 quarries around Prague and at Karlstein, Trilobites are exceedingly 

 rare in this formation. At Lochkov, Gromus abounds, to the ex- 

 clusion of other genera in any abundance. At Listice, SpJicerexochus 

 is very abundant, though rare elsewhere ; other genera are rarer. 

 Near St. Johann, Calymene^ Cheirurus, Staurocephalus, Lichas^ 

 and Acidas])is are all abundant. In all these localities the rock 

 containing these fossils presents the same lithological characters. 

 At Lodenice, where the rock is somewhat different, Arethusina 

 abounds, although rare elsewhere. It is but fair to state that 

 the moUuscan fauna does not vary to this extent. 



Etage F. The two bands of this etage are of no great vertical 

 thickness, and are not often seen in contact with one another. At 

 present, a section is exposed in the quarries of Dvorec, near Prague, 

 in which f 2 is seen superposed upon f 1. A light yellow siliceous 

 band occurs between E and E in the Tachlovice valley, where f 1 

 appears to be absent. 



E f 1 consists of blackish crystalline, thin-bedded limestones, 

 with thin black shales. It is very black in the valley near Lochkov, 

 not so much so at Dvorec and in the Slivenec valley ; it does not 

 seem to be of very wide extent. 



E f 2. A very white crystalline limestone, except where stained 

 pink by haematite. It is very well developed at Koneprus, and 

 is not found all over the basin. Eossils are very locally distributed, 

 even in the same sections. E f 2 contains some chert bands in 

 places, as in the Tachlovice valley. 



Etage G consists of two limestone bands, with an intermediate 



