[PENHALLOW] DEVELOPMENT OF CERTAIN MARSH LANDS 37 
latter type occupy small depressions or basins of the general rock forma- 
tion where they receive abundant water through drainage of the sur- 
rounding areas and lose little except through evaporation. 
All of these bogs being within easy reach of one another, and 
individually presenting a very limited area, they can be studied with 
the greatest ease and thoroughness. The ideal conditions they present 
in these respects render them of great value for the complete elucidation 
of important ecological questions, and if they could be systematically 
studied throughout a long term of years—say twenty or forty—they 
would undoubtedly yield some of the most profitable results. It is not 
our present purpose, however, to enter more fully into these aspects of 
the question at present. Our special purpose will be sufficiently accom- 
plished by directing attention to such features of these upland bogs as 
may serve to emphasize the various stages of development noted in the 
formation of the salt marshes. 
Discussing these bogs with reference to their sequence in develop- 
ment, the first one studied shows a clear, central water field. Toward 
the shore, where sphagnum has already formed a fairly firm base, loose- 
strife has gained a hold, apparently without being preceded by the forms 
of plants usual in such cases. Close in shore, on the more elevated areas, 
the dominant vegetation is composed of a dense growth of Cyperaceæ. 
The second bog‘occupies an irregular area about two hundred by 
three hundred feet in extent, bordered by a bold shore bearing Pinus 
strobus and Picea rubra. The central area is occupied by a water field 
of limited extent, showing a later stage of development than the pre- 
ceding. Nearly one-half the entire area is occupied by a pure sphagnum 
growth upon the surface of which there is already an abundant develop- 
ment of Menyanthes trifoliata. This vegetation as a whole, gives a direct 
clue to the character of the remains found in the marsh at the top of 
the sphagnum zone, since there.is an exact correlation between the two 
in point of development, and the nature of the vegetation. 
Here and there, slightly more elevated areas form small islets which 
are occupied in part by Aspidium spinulosum; but somewhat more than 
one-half the entire area of the bog is occupied by a growth of Cassandra 
calyculata, the relation of which to the other vegetation zones exactly 
corresponds with the cassandra zone of the marsh. 
The third bog is of very limited size, being only about thirty by 
fifty feet in area. It is entirely devoid of a water field. Indeed its 
growth has progressed beyond the sphagnum stage, and the greater 
portion of it is in the cassandra stage. Thus it is seen that the whole 
central portion is occupied by Cyperaceæ, Cassandra calyculata and Vac- 
