280 EMMERICH ON THE MORPIIOLOGY, CLASSIFICATION 
granulatus, Wahlb. These last-mentioned slates, which have 
not yet been met with in Russia, are characterized by the com- 
mon Ph. mucronatus, with which some other peculiar forms are 
likewise associated, viz. Nuttainia laciniata (Lich.), Dalm., and 
Odontopleura centrina (Cal.), Dalm. The limestone of Gothland 
contains a greater number of characteristic forms, viz. Calymene 
Blumenbachii, Encrinurus punctatus, Gerastos concinnus, Pha- 
cops caudatus, and Odontopleura crenata, n. sp. There are 
therefore but few northern Trilobites found simultaneously in 
several members of the palzeozoic series; on the contrary, they 
are rather restricted to individual subdivisions, in which, however, 
they occur in the greatest horizontal extension. The Russian 
and Swedish transition rocks exhibit the most beautiful coinci- 
dence in respect to the Trilobites, as well as in their other fossils 
(Orthoceratites, Brachiopoda, Crinoidea). This coincidence 
no doubt extends likewise to the transition rocks of Southern 
Norway, which abounds in fossils ; at least the same fossils have 
been found in them as in Sweden; even the Cal. Blumenbachii 
of Gothland limestone is not wanting. The constituents of that 
rock are however principally black slate, with subordinate lime- 
stone and likewise black. This homogeneity of the deposits 
renders the separation of the respective subdivisions more diffi- 
cult there than in the other parts of Northern Europe. 
The above formations are covered in Russia by a second power- 
ful rock formation, which constitutes the Waldai plateau ; thence 
extending itself to the extreme North of Europe. It is composed 
of sand and sandstone, corresponding with the old red of En- 
glish geologists, and of a limestone abounding in Producta and 
Spirifera, viz. mountain or carboniferous limestone. Two spe- 
cies of tails of Trilobites are met with in the latter, dsaphus 
Eichwaldi and Brongniarti, Fisch. v. Waldh.; they correspond 
exactly with caudal shields of Griffithides and Phillipsia, Portl., 
which are likewise peculiar to the mountain limestone in En- 
gland. 
2. British Islands—The British palzozoic rocks have still 
more members than those of Northern Europe. In addition to 
this it must be stated that the relations of strata are not so 
readily apparent or striking; its strata are arranged either in 
lines or in centres of elevation, and are partially changed by the 
influence of plutonic rocks. Taking these various causes into — 
consideration, it cannot surprise us that only the most strenuous — 
