110 
TENTH REPORT. 
that at one time the bottom of the deposit was above the high water level, 
and was a tree-covered swamp. Subsidence began, and the water, still fresh, 
was for some reason held back in the swamp to a higher level than formerly, 
so that the trees were drowned. The soil became so wet that humification 
ceased, the trees died, were replaced for a time by shrubs and then, because 
of still higher water level in the soil, by the sedges and bulrushes. For a long 
time the upbuilding seems to have been about equal to the rise in water, 
which here was due to subsidence of the bottom, but finally the level of the 
surface became so low that the tide reached it, and from that time on, the 
silt-laden salt water has left a clear record. The total subsidence recorded is 
not far from 6 feet, and the rate of subsidence was equal to the rate at which 
upbuilding occurred. The subsidence is apparently still continuing at about 
the same rate, as if it were going on more rapidly, there would be an invasion 
of plants more tolerant of salt water; if less rapidly, the surface would be 
built up and the present plant society would give place to one less “ halo- 
phvtic ” or' salt-loving. If subsidence had stopped, the same indication 
would be present. 
At various points in New Hampshire and Maine, similar fresh water peat 
beds were found in salt marshes. One study, made at Cutt’s Island, Maine, 
was of especial interest, as it gave evidence of an elevation followed by 
subsidence. Below the present low water mark was found the character- 
istic deposit made by one of the salt marsh grasses which grows only above 
the half tide mark; this was capped by a turf identical in structure with the 
• present surface deposit of the marsh, also below the present low water; 
superposed on this, was material which could have been formed only in a fresh 
water pond, above which in order came layers of sedges, shrub and moss, 
and then abruptly the peculiar mud, containing the underground stems of 
the salt thatch, appeared in the section, and at the top was the present turf. 
In another part of the same marsh, nearer the shore, the fresh-water material 
was considerably thicker, and the upper layers were abundantly filled by 
tree remains, both conifers and broad-leaved types being present. Evi- 
dently here the subsidence proceeded rather slowly, and the tide invaded 
the swamp gradually. This phase of the study of peat beds possesses so 
much interest, that one is tempted to prolong the discussion, but, after one 
more illustration, this time from North Carolina, it must be left. 
Along the sounds of this state, especially those more remote from the sea 
and where the water is practically fresh, peat beds formed on a subsiding 
bottom are not uncommon. One such, near Elizabeth City, on Albemarle 
Sound, was more than 18 feet deep, and the structure of the peat was such 
that it is reasonably certain that the present conditions have continued 
•throughout the time of its formation, that is, subsidence has been nearly 
uniform, with possibly slight halts, -since it began. Halts in the subsidence 
would be indicated in such beds, by an accumulation of tree remains at defi- 
nite depths. In a rather hasty examination of the deposit, no such tree 
bearing layers were found. 
As to the rate of subsidence going on here, studies of the living plants 
growing on the deposit should show this: for example: one of the striking 
phenomena of these sounds to a stranger in the region, is the occurrence of 
living cvpress trees growing in the water of the sounds, 100 yards, a quarter 
of a mile, or even longer distances from the shore; the question naturally 
arises, how did they get there and the obvious answer is Topsy’s, “they jest 
growed.” But even the least botanically inclined individual knows that 
no tree ever started from seed in several feet of water a quarter of a mile from 
