802 ■ REroET — 1892. 



■by ttem at deptlis of 474 and 622 fathoms respectively. There is, in short, a 

 broad resemblance between the coasts of the entire Arctic and North Atlantic 

 regions down to the latitudes already mentioned. Everywhere they are 

 irregular and fringed with islands in less or greater abundance — highly denuded 

 and deeply incised plateaus being penetrated by fiords, while low-lying and 

 undulating lands that shelve gently seaward are invaded by shallow bays and 

 inlets. Comparing the American with the opposite European coasts one cannot 

 help being struck with certain other resemblances. Thus Hudson Bay at once 

 suo-gests the Baltic, and the Gulf of Mexico, with the Caribbean Sea, recalls the 

 Mediterranean. But the geological structure of the coast-lands of Greenland 

 and North America betrays a much closer resemblance between these and the 

 opposite shores of Europe than appears on a glance at the map. There is some- 

 thing more than a mere superficial similarity. In eastern North America and 

 Greenland, just as in Western Europe, no grand mountain uplifts have taken 

 place for a prodigious time. The latest great upheavals, which were accompanied 

 by much folding and flexing of strata, are those of the Apallachian chain and of the 

 coastal ranges extending through New England, Nova Scotia, and Newfoundland, 

 all of which are of Palreozoic age. Considerable crustal movements affected the 

 American coast-lands in Mesozoic times, and during these uplifts the strata 

 suffered fracture and displacement, but were subjected to comparatively little 

 folding. Again, along the maritime borders of North-east America, as in the 

 corresponding coast-lands of Europe, igneous action, more or less abundant in 

 Palreozoic and early Mesozoic times, has since been quiescent. From the mouth of 

 the Hudson to the Straits of Florida the coast-lands are composed of Tertiary and 

 Quaternary deposits. This shows that the land has continued down to recent 

 times to gain upon the sea — a result brought about partly by quiet crustal move- 

 ments, but to a large extent by sedimentation, aided, on the coasts of Florida, by 

 the action of reef-building corals. 



Although volcanic action has long ceased on the American sea-board, we note 

 that in Greenland, as in the West of Scotland and North of Ireland, there is abun- 

 dant evidence of volcanic activity at so late a period as (he Tertiary. It would 

 appear that the great plateau-basalts of those regions, and of Iceland and the 

 Fieriie Islands, were contemporaneous, and possibly connected with an important 

 crustal movement. It has long been suggested that at a very early geological 

 period Europe and North America may have been united. The great thickness 

 attained by the Paheozoic rocks in the eastern areas of the latter implies the 

 existence of a wide land surface from which ancient sediments were derived. 

 That old land must have extended beyond the existing coast-line, but how far we 

 cannot tell. Similarly in North-west Europe, during early Paleozoic times, the 

 land probably stretched further into the Atlantic than at present. But whether, 

 as some think, an actual land connection subsisted between the two continents it 

 is impossible to say. Some such connection was formerly supposed necessary to 

 account for the emigration and immigration of certain marine I'orms of life which 

 are common to the Palpeozoic strata of both continents, and which, as they were 

 probably denizens of comparatively shallow water, could only have crossed from 

 one area to another along a shore-line. It is obvious, indeed, that if tlie oceanic 

 troughs in those early days were of an abysmal character, a belt of shallow water 

 •would be required to explain the geographical distribution of cosmopolitan maiine 

 life-forms. But if it be true that subsidence of the crust has been going on through 

 all geological time, and that the land areas have notwithstanding continued to ex- 

 tend over the continental plateau, then it follows that the oceanic trough must be 

 deeper now than it was in Palreozoic times. There are, moreover, certain geological 

 facts which seem hardly explicable on the assumption that the seas of past ages 

 attained abysmal depths over any extensive areas. The Palteozoic strata which 

 enter so largely into the framework of our lands have much the same appearance all 

 the world over, and were accumulated for the most part in comparatively shallow 

 water. A petrographical description of the Paltoozoic mechanical sediments of 

 Europe would serve almost equally well for those of America, of Asia, or of 

 Australia. Take in connection with this the fact that Piila;ozoic faunas had a 



