THE CAMBRIAN SYSTEM 103 



I. Olenellua Beds, chiefly sandstones homotaxial with the Hartahill 

 quartzite and Caerfai Beds, 350 to 550 feet 



4. Phosphatic limestone (few fo- 



3. Sandy shales with Olenellus Kjerulfi and Arionellug prinumu 

 (5 to ]0 feet). 



2. Fucoid sandstone with Obolella favona, 200 to 350 feet. 



1. Eophyton sandstone with Mickvritzia monilifera and the 

 markings called Eophyton and Cruziana, 150 to 200 feet. 



The basal sandstones rest unconformably upon the Archtean 

 gneisses. 



5. Russia 



In the Baltic provinces of Russia there is a still more remarkable 

 development of the Cambrian System. The arenaceous division is 

 partly replaced by blue clay, and the black trilobite shales are 

 absent. The succession is as follows : 



Ft. 



^ f 6. Glauconitic sand with Obolus and Siphonotreta ... 10 

 J 5. Shales with Dictyograptus and Bryoyraptus ... 20 

 &. j 4. The Ungulite sandstone full of Obolus Apollinis and other 



minute Brachiopods ....... 4 



^ f'3. Alternating clays and sandstones with Olenellus Michwitzi, 



Mic.kioitzia monilifera, and a Scenella . . .50 



c I 2. The blue clay, without fossils .... . 300 



" \1. Ferruginous sandstones, resting on granitoid rock . . 300 



684 



Professor F. Schmidt 30 has pointed out that the base of the 

 Ungulite sandstone is sharply divided from the beds below, and some- 

 times contains pebbles derived from them. Hence there appears to 

 be a gap at this point, which will account for the complete absence 

 of any representatives of the Paradoxides and Olenus shales, 

 unless the thin band of Ungulite sandstone is a partial equivalent 

 of the latter. The underlying clays and sandstones are evidently 

 the equivalents of the Fucoid and Eophyton sandstones, while the 

 two highest members are comparable with the beds which occupy 

 the same position in Sweden. 



6. Germany and Bohemia 



It is very probable that Cambrian rocks underlie the greater 

 part of Germany, but they are only exposed in a few places. 

 One of these is the Hohe Venn, south of Aix-la-Chapelle, where 

 there are slates, quartzites, and phyllites, resembling those of the 

 Ardennes and containing both Oldhamia and Dictyograpttu. 

 Another and larger area is found in the Fichtel Mountains and the 



