168 BOTANICAL GAZETTE [SEPTEMBER 
rapidly eroded by the strong tidal currents, which, in their 
onward rush to the northeast, carry the detritus whirling in 
suspension, to drop it as their force is checked by their quiet 
spread over the marshes at the highest tides. Thus, the sea 
bottom supplies the materials, the rush of the tidal currents the 
power to remove, carry and lift them, and the quiet of the 
waters at the turn of the tide the condition allowing them to be 
dropped. In this way the sea is building up the land, perhaps 
on a greater scale here than elsewhere on the globe.‘ 
The quantity of mud needed to form the marshes has been 
immensely great. Not only do they cover many square miles, 
but borings show that they can be as deep as eighty feet at least ; 5 
and moreover, the marsh mud extends also everywhere under the 
bogs and shallow lakes clear to their utmost bounds. To supply 
this quantity, the channel to the bay (Chignecto Channel) must 
have been enormously widened and deepened, and hence it must 
have been very small when the process began. The sea has 
quarried out the channels, and the marshes are the debris. This 
process has been aided, or, perhaps more properly, has been 
allowed, by the recent subsidence of this region, of which the 
indisputable evidence is found in the buried forests well known 
to exist at several points under the marsh much below high-tide 
level. Dawson first described the stumps of a beech and pine 
forest, the wood still sound, rooted on Fort Lawrence Ridge, 
thirty to thirty-five feet below high-tide level. Chalmers and 
others have described other cases, particularly stumps laid bare, 
over thirty feet under the surface, in the ship-railway dock,® and | 
+The power of these tidal currents in eroding the apr dod = has been well 
set forth by Matthew, in his “ Tidal erosion in the e Bay of Fundy. 
5 Chalmers, Geological Report 1885, M, 129: according to the same investigator 
however (of. ci#. 41) this depth appears to beso great in consequence of a fault at this 
He apparently means that the downthrow took place while the mud was 
eke ng. The depth of baat = assigned to the mud at this place by Trueman, 
is based, as he informs me, upon the recollection of a resident as to the depth of the 
boring described by Mr. pi The official figures of the latter, however, make 
the depth somewhat under 8o feet 
°The ship-railway, a great work designed to transport vessels across the Isthmus 
of Chignecto by rail in lieu of a canal. Though over three-fourths finished, work 
upon it has been suspended and is unlikely to be resumed. 
