[MATTHEW] CLIMATIC ZONES IN DEVONIAN TIME 141 
parable with the Tournasian of Belgium, which continental geologists 
are content to regard as the base of the Carboniferous System. If this 
is a correct view to take, all the measures in this terrane below this lime- 
stone, are to be regarded as Upper Devonian; the paleontological evidence 
therefore brings us to the same result as Mr. Fletcher obtained is study- 
ing the structure. 
When it comes to the question of rating the value of palæobotanical 
evidence of the age of a formation or terrane against the marine palæo- 
zoological data, I think most students of paleontology will admit that 
the latter is the more reliable, because it is based on the inhabitants of 
the open sea which now have, and in the past also have had free com- 
munication in all parts of the world; and moreover occupy a much 
larger area of the earth’s surface, than is open to the growth of land 
plants. No more exact standard of the changes of Life in past ages can 
be obtained than that supplied by the plankton and nekton of the open 
sea; hence the value of the Brachiopoda and of marine Crustacea in 
deciding questions of the comparative age of geological strata. It is 
upon these grounds, which will be more fully explained as we proceed, 
that the base of the Carboniferous limestone is assumed to be in this 
region the base of the Carboniferous system. 
The Southern Range of Basins. 
We come now to speak of the range of basins of Upper Devonian 
rocks that are found in Acadia (the Maritime provinces of Canada). 
These basins are in a belt of country extending from the boundary of 
the United States near the Bay of Fundy, through southern New Bruns- 
wick and northern Nova Scotia to Cape Breton. They are along and 
on each side of the forty-fifth parallel of North latitude and thus south 
of all northern upper Devonian terranes except that of the Pennsylvanian 
and New Yorkhighlands. In this narrow southern belt of basins a much 
greaterdiversity of floras is to be found than in the northern continent- 
wide belt, previous considered. In only one basin of the southern belt is 
there a “Devonian” type of vegetation and the phases of plant-life that 
mark the others are such as heretofore have been thought to be limited 
to the Lower Carboniferous terranes and the Coal Measures. 
But as these phases of vegetation are in Acadia found in terranes 
below the Lower Carboniferous limestone it is plain that they are not 
Lower Carboniferous—unless we add to the Carboniferous the great 
mass of sediments which here lie below the marine faunas that in Europe 
are thought to mark the dividing line between the Devonian and the 
Carboniferous. 
