308 Hutt—On the Geological Age of the North Atlantic Ocean. 
But it may be replied, that ¢/s distribution cannot be taken as representative 
of very ancient geological epochs, inasmuch as the marine formations of Archean 
and Paleozoic times must originally (@ e. before denudation and concealment by 
newer strata) have overspread the greater portion of the existing lands; and inas- 
much as these formations represent the seas of those periods, the lands which 
yielded the sediments of which they are composed must have lain where now the 
ocean waters are spread. 
So much, then, for the general question of the interchange of the present 
oceans and continents in early geological times. I must now pass on to the special 
consideration of the evidence afforded by the lands bordering the North Atlantic, 
with a view to ascertain to what extent it bears on the question of the age of 
this (to us) the most familiar and interesting of all the oceans of the world. 
Continuing to use the three principal factors I have already mentioned, namely, 
the groups of strata known as the ‘“ Archeean,” or ‘‘ Laurentian,” the ‘ Silurian,”* 
and the ‘‘ Carboniferous,” I shall call upon them in succession for the evidence 
they are capable of supplying. 
(1) The Archean or Laurentian Group.t—This great group of crystalline strata 
seems to form everywhere in Europe and the British Isles the floor of all more 
recent deposits, from the Cambrian and Lower Silurian upwards. In the British 
Isles the beds rise from beneath the representatives of the Cambrian and Silurian 
systems in the Northern Highlands of Scotland, and the Highlands of Donegal 
and Galway, besides occurring perhaps in other, more central, districts. They 
form a large portion of the Scandinavian promontory, and of Finland, passing 
beneath the Silurian beds of Russia and of Southern Sweden. They occur again in 
Normandy and Central France, in the north of Spain and Portugal, and they form 
the floor of the Silurian basin of Bohemia, and of the rocks of the Hereynian 
Forest, in the centre of Europe. 
To sum up, then, we find over the British and European area metamorphic 
rocks, everywhere forming the floor upon which have been laid down, in highly 
discordant positions, the fossiliferous deposits of more recent times, ranging from 
the Lower Cambrian upwards. This series is of vast, but unknown, thickness, as 
its base nowhere appears over the surface ; and consequently the strata stretch to 
unknown distances beneath the waters of the Atlantic Ocean. We are therefore 
unable anywhere to discover over the land-surface a trace of the pre-Archean 
lands from which these strata were originally derived. 
(a) America.—Turning our attention to the American side of this ocean, we find 
* The Lower Silurian is the division which is of most use in this inquiry, owing to its vastly 
greater extension ; in some regions the upper and lower divisions are so greatly unconformable as to be 
stratigraphically distinct formations, as in the British Isles. 
+ In this inquiry I have to assume that the Archean rocks of Europe and North America are 
representative in time, a view not capable of direct proof, but in the highest degree probable. 
