1909] Bartlett,— Submarine Bog at Woods Hole 225 
Microscopical examination of wood from the stumps has shown 
that the trees were Chamaecyparis thyoides. Some of them, between 
three and four feet in diameter, were larger than any trees of this 
species now found in the vicinity of Woods Hole. The wood is still 
solid, and wonderfully preserved. When cut after the salt water has 
dried out, it is as fragrant as though fresh. Besides wood, the peat 
contains seeds of Chamaecyparis and countless little rod-like particles 
of resin which appear to have been derived from the glands on its 
scale-like leaves. Other identifiable remains are Sphagnum, seeds 
of an alder, and achenes of sedges. ‘Throughout the entire marsh the 
character of the peat is the same. Wood is found at all depths. ‘This 
fact, taken in conjunction with the general topography of the depres- 
sion, leaves no doubt but that our marsh is a kettle hole Chamaecyp- 
aris bog drowned by the sea. This conclusion is borne out by a 
study of the zonation of vegetation in the marsh, for in the extreme 
landward part Chamaecyparis is still growing, and peat similar to that 
which underlies the salt-marsh is still forming. Soundings in this 
part of the bog show that its history as a Chamaecyparis bog has been 
unbroken. It has never been submerged below sea level, for there is 
no stratification of the peat which would indicate this. In recent 
times, however, there have been no trees in this part of the bog as 
large as those found at depths of three or four feet, which correspond 
in age to those exposed in the peat at the edge of the salt-marsh. 
No doubt most botanists are familiar with Shaler's papers ! in which 
the zonation of salt-marshes and the plant succession concomitant 
with their upward growth are described. Zostera and various sea 
weeds, growing densely on shallow bottoms, retard the velocity of 
tidal water so that it deposits among them part of the sediment which 
it carries in suspension. When by this means a tidal flat has been 
built up sufficiently, Spartina glabra establishes itself and collects 
sediment even more efficiently than the eel-grass. Finally, when the 
marsh has been built practically to high tide level, Spartina glabra is 
for the most part replaced by Spartina patens and Juncus Gerardi. 
A growing marsh shows these three zones, which are represented in a 
vertical section of a mature marsh by three corresponding strata. 
1 Sea-Coast Swamps of the Eastern United States. 6th Ann. Report U. S. Geol. 
Surv. (1884-85) p. 359. 
Beaches and Tidal Marshes of the Atlantic Coast. National Geographic Monographs, 
і no. 4 (1895) p. 137. 
