658 - STRATIGRAPHICAL GEOLOGY. — [Boox VI. 
glomerates, sandstones, and dark shales with limestone, and containing 
Paradoxides Tessint and P. Forchhammeri; and (2) an upper zone (150 
feet) composed of black slates (Alum slates) and fetid limestone, with 
Olenus, &. In Sweden the Cambrian series comprises (1) ‘‘ Hophyton 
and Fucoid Sandstones”—sandstones and green shales with Hophyton, 
Palzophycus, and numerous other somewhat obscure impressions (Regio 
fucoidarum of Angelin), and the first traces of tke primordial fauna - 
Theca, Obolus, &c.); thickness from not more than 50 or 60 to 400 feet. 
t5) ** Paradoxides Beds ””—black alum slates, with an intercalated band 
of limestones (Andrarumskalk); united thickness only a few feet. Ac- 
cording to Linnarsson the group may be subdivided into six zones, each 
marked by its characteristic trilobite, viz., 1. Paradowides Kjerulfi; 2. P. 
Tessini ; 3. P. Davidis ; 4. P. Oelandicus ; 5. P. Forchhammeri (= Andrarum — 
limestone); 6. Agnostus levigatus. The same author gives a census of the 
fauna of these beds, from which it appears that they contain 44 species of. 
trilobites—1 Leperditia, 3 pteropods (Theca), 11 brachiopods, and a — 
sponge. (3) “Olenus schists” comprising the upper part of the black 
alum slates containing Olenus, thickness not more than 40 or 50 feet, 
yet believed by Linnarsson to contain paleontological equivalents for 
every horizon of the thick English Lingula flags. (4) ‘‘ Dictyonema 
schists,”;full of Dictyonema flabelliforme with a Dichograptus and Obolella. 
A remarkable group of primordial trilobites has recently been obtained 
from a limestone (Haulans zone) lying probably about the horizon of the 
Tessint zone in Scania. The forms are for the most part peculiar to Scan- — 
dinavia, and include species of the genera Paradoaides, Conocoryphe, Lios- 
tracus, Solenoplewra, Agnostus, Hyolithus (Theca), Lingulella, and Obolella.* 
It is uncertain whether the Scandinavian Cambrian series should be 
regarded as representing the whole of the enormously thicker British 
system or only the upper part of it. On the former supposition we 
must conceive that while the British area underwent a subsidence of 
more than 20,000 feet the Scandinavian region did not sink more than 
about a hundredth part of that amount. The Cambrian formations 
appear to thin out eastwards from Sweden, for they have not yet been 
satisfactorily recognized among the undisturbed Palzozoic sediments of 
north-western Russia. ; 
In Central Europe Cambrian rocks appear from under later accu- 
mulations in Belgium and the north of France, Spain, Bohemia, 
and the Thuringer Wald. ‘The most important in France and 
Belgium is that of the Ardennes, where the principal rocks are grit, 
sandstone, slates, and schistose quartzites or quartz-schists (quartzo- 
phyllades of Dumont), with bands of whet-slate, quartz-porphyry, 
diabase, diorite, and porphyroid. According to Dumont these rocks, 
comprehended in his “Terrain Ardennais,” can be grouped into three 
great subdivisions—Ist, the “‘Systéme Devillien,” pale and greenish 
quartzites with slates or phyllades, containing Oldhamia radiata and 
annelide tubes; 2nd, the “Systéme Revinien,” phyllades and black 
pyritous quartzites from which Dictyonema sociale, Hophyton Linneeanum, 
and worm-burrows have been obtained; 3rd, the “Systéme Salmien ” 
' Kjerulf, “Geologie des Siidl, und Mittl. Norwegen,” 1880. W. Brogger, Nyt. 
Mag. 1876. Geol. Foren. Forhandl. 1875-76. Angelin, “ Palwontologia Suecica,” 
1851-54, Dahil, “ Vidensk-Selsk. Forhandl.” 1867. Linnargsson, * Svensk. Vet. Alcad. 
Handl.” 1876, iii. No. 12; Geol. Mag. vi. (1869), p. 393; iii. 2nd Dec. 1876, p. 145, “Om 
Faunen in Kalken med Conocoryphe exulans,’ Stockholm, 1879. Lundgren, in text to 
Angelin’s Geol. Map of Scania, N. Jahrb, 1878. Lapworth, Geol, Mag. 1881, p. 260. 
