FLORA. 203 
and feeble, as is the case with all beginnings. We cannot 
tell what the temperature which first admitted of this may 
have been, nor what were the first forms which presented 
themselves. Coincidences which are but of rare occur- 
rence would have been necessary to give us fossil remains 
of that early period; nor are all organisms capable of 
leaving tangible remains. We may infer from what we 
know of existing organisms, that most probably these 
primitive organisms were of a soft consistency, integuments 
and skeletons being the result of later development of the 
primary types. 
‘The primitive strata, notwithstanding their thickness, 
supply us with few means of studying by these fossils the 
character of the few widely separated vegetables and 
animals inhabiting the waters during their deposit, but 
the absence of these is no proof that vital organisms were 
then non-existent. There are many remarkable geological 
facts which are of such a nature as to give rise to the 
thought that life had its first home, if not at the Pole 
itself, at least in the neighbourhood of it, and that once 
developed, it remained for a long time more active and 
more reproductive in the countries which border on the 
Polar Circle and the higher latitudes. The most ancient 
fossiliferous deposits, which are, at the same time, those 
most rich in organic remains, are found comprised within 
the Northern Zone. They abound, moreover, in the cold 
portion of that zone, from the 50th to the 60th degree of 
North latitude, and still further to the north. We meet, 
it is true, with Silurian formations in the south of Spain, 
and in America, at a latitude corresponding nearly to the 
35th degree of North latitude; but the most celebrated 
localities are situated more to the north, in Bohemia, in 
England, in Scandinavia, and in the United States. The 
Laurentian system acquires its greatest development in 
Canada; and the palaeozoic rocks associated with crystal- 
line masses cover a considerable portion of the Polar lands 
which stretch away to the north of the American lakes, 
It is evidently the same with the parts of the ocean which 
