1919] Fernald,— Ranges of Pinus and Thuja 57 
extent of determining the character of the flora as calcifuge or calci- 
phile, without its being at all evident in the physical character of the 
soil, which would still be ‘granitic’ or ‘siliceous.’ Such observations 
in order to be critically decisive, clearly require that the observer 
should be, not merely a systematic botanist, nor a mere geologist or 
chemist, but all these combined. There is good reason to believe 
that most or all of these supposed contradictions would disappear 
before a critical physical and chemical examination of both the soils 
and the rocks from which they are supposed to have been derived. 
Contejean himself, in placing so many of his long catalogue of plants 
into the doubtful groups, suggests many cases in which the above 
considerations may explain the apparent discrepancies. 
at is a calcareous soil? The definition adopted for this volume 
has been given in a previous chapter (chapter 19, page 367); viz, 
that a soil must be considered calcareous so soon as it naturally supports 
a calciphile flora — the ‘lime vegetation’ so often referred to above 
and named in detail. Upon this basis it has been seen that some 
(sandy) soils containing only a little over one-tenth of one per cent. 
of lime show all the characters and advantages of calcareous soils; 
while in the case of heavy clay soils, as has been shown, the lime-per- 
centage must rise to over one-half per cent. to produce native lime 
growth.” ! 
It is, therefore, premature to say that in the region of its almost 
continuous occurrence, from New Brunswick and adjacent Quebec 
across northern New England, northern and central New York, 
southern Ontario, Michigan, Wisconsin and Minnesota, Thuja con- 
es itself to calcareous soils for, like many other plants in the area 
where they are dominant, Thuja may prove to be ubiquitous or some- 
what indifferent to moderate differences of soil ; but that its finest 
development in this region is in the calcareous tracts cannot be seri- 
ously questioned. : 
n New Brunswick and Maine Thuja likewise delights in the river 
alluvium and terraces along the principal streams, which have their 
upper sources in calcareous tracts for, as Hilgard clearly shows,? 
although in water draining from mixed but unmanured soils “lime 
= the ingredient most abundant,” river waters show a marked diminu- 
tion “ especially of lime . . . indicating a deposition of lime carbonate 
1 Hilgard, Soils, 523, 524 (1907). 
* Hilgard, Soils, 24 (1907). 
