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temperate tides that lave our own favoured sliores cherish a submarine popula 
tioii iiitorincdiatc in cliaractcr between both." Thus, ehiclly by tiie labours of 
Forbes, the Euroj)ean sea-aroa iuis been divided into six zoological [jroviuees, 
wilhin which he considered there were to b(! reckoned as many distinct centres 
of creation. Tiie lirst and norihcrnniosi being the Arctic, " extending through- 
out tiiat portion of tlie European seas within the Arctic Circle. The second, 
the Boreal " including the seas which wash tlie shores of Norway, Iceland, the 
Faroe, and the Zetland Isles. The tiiird, the Celtic, " in which rank tiie British 
seas, the Baltic, and the shores of the continent from Bohuslan to tlie Bay of 
Biscay." The fom'th, the Lusitauian, includes the Atlantic coasts of the Pen- 
insula. The fifth, the Mediterranean, includes also the Black-sea ; and lastly, 
tlic Caspian, a region now completely isolated from all the others. All these 
provinces are succinctly but perfectly, as far as existmg knowledge goes, con- 
sidered in their geograpliieal, physical, and geological relations, and the 
characteristic life-forms of each carefully made out. Of these it was suggested, 
however, by Forbes that the Mediterranean and its dependencies may possibly 
be a chain of offsets from the Lusitauian area; while Mr. Austen seems to con- 
sider the Boreal fauna as a modification of the Arctic. In the chapter on the 
geographical distribution of shells in Mr. Woodward's " Manual of Mollusca," 
the lists of shells occurring in the several marine regions are tabulated, and these 
lists will be found to be useful companions to this " History of the European 
Seas." In the ninth chapter " On the Distribution of Marine Animals," 
amongst other interestbig topics, that of those " outliers," or remarkable 
asseniblages at spots, often far distant from the present boundaries of a pro- 
vince, of animals of its characteristic species, is treated very forcibly in 
its geological aspect. Such assemblages, for example, often occur within 
our own Celtic province, and are so peculiar and so isolated that they can not 
be accounted for by any facts comieeted with the present disposition of cur- 
rents, or other transporting influences. They are " usually located in a hole 
or valley of considerable depth, from eighty to beyond one hundred fathoms, 
and consist of species of moUuscs of a more northern character than those of 
the zone or province in which they occur." 
"The explanation wliich Edward Forbes gives of these 'outliers' is as 
follows : — When the bed of the sea of that period, when in our latitudes the 
fauna was more northern than it is now, \va.s upheaved, the whole was not 
raised into dry land, but tracts of greater depth, and which consequently were 
tenanted by peculiar forms, still remained luider water, though under different 
depths. In these changes a portion of a fauna would be destroyed, but such 
species as coidd endure alterations in vertical range would live on." 
Of such outliers, or isolated groups of fossil remains, Mr. Austen quotes the 
remarkable instance, noticed by M. Barrande, of a patch in one of the lower 
divisions of the great Palaeozoic series of Bohemia, of as many as sixty species 
of forms not agreeing with those characterizing tlie horizon in which tliey occur. 
These forms are surmounted by beds containing the characteristic species of 
the same lower division, but the sixty species thus isolated appear again as a 
component part of the fauna of the "upper division" of the same palaiozoic 
series. Sucli isolated assemblages are regarded by Mr. Austen as true outliers, 
and " will serve to suggest curious and interesting geological inferences in the 
earlier history (both natural and pliysical) of the European area." 
Of the antiquity of tiie fauna of the European seas, Mr. Austen writes : 
" The fauna of tlie European seas dates back its origin or first appearance to 
times which, on the scale of the geologist, follow next after the Nummulitic 
period (Eocene). So far as European seas are concerned, they do not contain 
a single species in common with the forms of the nummulitic group. The 
earliest records of the occupation of the Atlantic by any existing forms are 
