Part II. Sect. vy. § 1.] PERMIAN. 751 
vary in size up to blocks a foot or more in diameter. Sometimes, 
these stones are well rounded, but in many places they are only 
partially so, while here and there they are quite angular and then 
constitute breccias. ‘The pebbles are held together by a brick-red 
ferruginous, siliceous, sandy, or argillaceous cement. The sandstones 
are likewise characteristically brick-red in colour, generally with 
green or white layers and spots of decoloration. The marls show 
still deeper shades of red, passing occasionally into a kind of livid 
purple; they are crumbling sandy clay-rocks, sometimes merging 
into more or less fissile shales. Of the aryillaceous beds of the system 
the most remarkable are those of the marl-slate or Kupferschiefer—a 
brown or black often distinctly bituminous shale or marl, which in 
certain parts of Germany is charged with ores of copper. The 
limestone, so characteristic a feature in the “ Dyas” development of 
the system, is a;compact, well-bedded, somewhat earthy, and usually 
more or less dolomitic rock. It is the chief repository of the 
Permian invertebrates. With it are associated bands of dolomite, 
either crystalline and cavernous (Rauchwacke) or finely granular and 
crumbling (Asche); also bands of gypsum, anhydrite, and rock-salt. 
In certain localities (the Harz, Bohemia, Autun) seams of coal are 
intercalated among the rocks, and with these, as in the Coal-measures, 
are associated bituminous shales and nodular clay-ironstones. In. 
Germany and in the south-west of Scotland the older part of the 
Permian system contains abundant contemporaneous masses of 
eruptive rock, among which occur porphyrite, melaphyre, and 
various forms of quartz-porphyry. 
Some of the breccias in the west of England contain striated 
stones, which, according to Sir A. C. Ramsay, indicate the existence 
of glaciers in Wales during the Permian period. 
The Permian system in Europe, from the prevalent red colour 
of its rocks, the association of dolomite, rock-salt, saliferous clays, 
gypsum, and anhydrite, has evidently been deposited in isolated 
basins in which the water, cut off more or less completely from 
the sea, underwent concentration until chemical precipitation could 
take place. Looking back at the history of the Carboniferous 
rocks we can understand how such a change in physical geography 
was brought about. The Carboniferous Limestone sea having been 
exciuded from the*region, wide lagoons occupied its site, and these, 
as the land slowly went down, crept over the old ridges that had for 
so many ages been prominent features. ‘The downward subter- 
ranean movement was eventually varied by local elevations, and 
at last the Permian basins came to be formed. As a result of these 
disturbances the Permian rocks overlap the Carboniferous, and even 
cover them in complete discordance.’ 
Life.—The conditions under which the European Permian 
rocks were deposited must have been eminently unfavourable to life, 
1 The discordance, however, sometimes disappears, and then the Carboniferous and 
Permian rocks shade into each other. 
