292 
THE GEOLOGIST. 
not represented ; although the genus Orthis is so rich in both coun- 
tries, it only counts two identical species, and the bulk of the iden- 
tical forms belongs to the deep-sea group B. M. Barrande has sug- 
gested that in those cases in which the fauna? are distinct in both 
countries, a limit between both may have existed similar to that now 
existing between the Red Sea and the Mediterranean, or between the 
Atlantic and the Pacific, and that when a greater number of identical 
species is found, it may be ascribed to the disappearance of this 
barrier. !My view ou the subject is dilFerent. Supposing that the 
first and second faunee are indeed httoral and sub-littoral deposits, 
the presence of open and somewhat deeper sea will alone be quite suffi- 
cient to account for the distinctness of these faunae, the deep sea 
forming an almost insurmountable bari'ier for such beings. Even in 
the third faunae only such forms will be found identical in both coun- 
tries, which have been able to pass over the depths of that Silurian 
ocean which separated Scandinavia from Bohemia. 
Let us for a moment abstract such species as are common to the 
Bohemia etage / and to Scandinavia, and only regard the lower etage 
e of the Bohemian Upper Silurian beds. This deposit offers fourteen 
species of Brachiopoda, in common with Scandinavia, and, as wo 
have seen above, eleven species in common with the " Colonies." 
In comparing the lists it is seen, that with the exception of Sjnri- 
gerina reticularis and Strophomcna eugltjplia, these two lists contain 
different names. I presume, therefore, that a further bathymetrical 
subdivision of that Silurian ocean existed, and that at its southern 
border the Httoral and siablittoral zones were inhabited by the fauna 
and do ; the next deeper by the species found in the " colonies ;" 
the deepest by those which have proved identical with Scandinavian 
deposits, Sping. reticularis and 8troi)h. eughjplia may have hved in 
both the noiddle and the deeper zones. 
M. Ban-ande names about sixty fossils as common to the " colonies" 
and the fauna e. Among these are eight trdobites and other crus- 
taceans, twenty Cephalopoda, twelve Acephala, but only eleven 
Brachiopoda and one Coral : four Cardiolae and eight other Cardiacea 
are found here, together with four Graptolites. The character of the 
small list of fossils common to the Upper Silurian of Bohemia and 
Scandinavia is quite difiFerent ; it contains a single Trdobite, very 
few Cephalopoda, but eighteen Brachiopoda and several Corals. 
Brachiopoda of the gToup B therefore, and Corals must, if my view 
be correct, have formed by far the greatest part of the population of 
the deeper part of the sea. 
Supposed a barrier of land to have existed between Scandinavia 
and Bohemia, and this to have been destroyed ; no cause can be 
given why merely Brachiopoda and Corals alone have passed the 
place where it formerly existed. Say, on the contrary, my view to be 
correct, then localities must be known in which such Brachiopoda 
and Corals occur alone, or nearly so, and are contained, not in sand- 
stone or shale, but in limestone, and these locahties may then be re- 
garded as formed in deep sea. Now such localities are indeed known, 
