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‘Parr IL. Suor. iii. (1) § 2.| DEVONIAN. _ 708 
persistence of general paleontological characters, in Eastern Thuringia, 
Franconia, Saxony, Silesia, the north of Moravia, and Hast Galicia. 
Devonian rocks have been detected among the crumpled formations of 
the Styrian Alps by means of the evidence of abundant corals, clymenias, 
_ gasteropods, lamellibranchs, and other organic remains. Perhaps in 
_ other tracts of the Alps, as well as in the Carpathian range, similar 
shales, limestones, and dolomites, though as yet unfossiliferous, but 
containing ores of silver, lead, mercury, zinc, cobalt, and other metals, 
may be referable to the Devonian system. 'To the west of the central 
area the system has been recognized by its fossils in the Boulonnais, 
where it is well exposed. In the Paleozoic ridge of Brittany, also, as 
was many years ago shown by De Verneuil and De Gerville, the system 
is represented by a series of fossiliferous strata which in the lower part 
consist of sandstones, chiefly of greenish colours, alternating with shales 
and followed by courses of grey or black limestone and shale, above 
which lies an upper group of shales, crumbling micaceous sandstones, and 
some limestone. Again the central Silurian zone of the Pyrenees is 
flanked on the north and south by bands of Devonian rocks (with broad- 
winged spirifers and other characteristic fossils), which have been 
greatly disturbed and altered. 
Throughout Central Europe there occurs, in many parts of the 
Devonian areas, evidence of contemporaneous volcanic action in the form 
of intercalated beds of diabase, diabase-tuff, schalstein, and porphyroid. 
These rocks are conspicuous in the “greenstone” tract of the Harz, in 
Nassau, Saxony, Westphalia, and the Fichtelgebirge. Here and there 
the tuff-bands are crowded with organic remains. It is also deserving of 
remark that over considerable areas (Ardennes, Harz, Sudeten-Gebirge, 
&c.) the Devonian sedimentary formations have assumed a more or less 
schistose character, and appear as quartzo-phyllades, quartzites, and other 
more or less crystalline rocks which were at one time supposed to belong 
to the Archean series, but in which recognizable Devonian fossils have 
been found. At numerous places also they have been invaded by masses 
of granite, quartz-porphyry, or other eruptive rocks, round which the 
present the characteristic phenomena of contact metamorphism (p. 578). 
With these changes may have been connected the abundant mineral 
_ veins (Devon, Cornwall, Westphalia, &c.), whence large quantities of 
iron, tin, copper, and other metals have been obtained. 
Russia.—In the north-east of Europe the Devonian and Old Red 
Sandstone types appear to be united, the limestones and marine 
organisms of the one being interstratified with the fish-bearing 
sandstones and shales of the other. In Russia, as was shown in the 
great work “Russia and the Ural Mountains” by Murchison, De 
Verneuil, and Keyserling, rocks intermediate between the Upper 
Silurian and Carboniferous Limestone formations cover an extent of 
surface larger than the British Islands. This wide development arises, 
not from the thickness, but from the undisturbed horizontal character of 
the strata. Like the Russian Silurian deposits, they remain to this day 
nearly as flat and unaltered as they were originally laid down. Judged 
by mere vertical depth, they present but a meagre representative of the 
massive Devonian greywacke and limestone of Germany, or of the Old 
Red Sandstone of Britain. Yet vast as is the area over which they con- 
_ stitute the surface rock, it probably forms only a small portion of their total 
