262 
H. Hamshaw Thomas. 
4. Sea Shore plants. 
5. (a) Field plants. 
(b) Ruderals. 
(c) Hedgerow (Kulturgransens) plants. 
6. Pine forest. 
7. Other mesophytes of meadows, deciduous woods, etc. 
8. Rock plants. 
9. Sand plants. 
According to the modern nomenclature of English ecologists, 
the natural vegetation of the island may perhaps be considered as 
belonging to four or five formations, viz., fen and calcareous bog 
formations, sandy drift forest formation, limestone rock and 
pasture formation, salt marsh formation. During a short visit to 
the island in July of this year I had the opportunity of noticing 
some of the chief characteristics of the first four of these. It 
may be of some interest if I give a short account of them. 
The Fenlands. 
A considerable portion of the lower-lying part of the country 
is dotted with small patches of fenland, and if, as may reasonably 
be supposed, the intermediate flat cultivated land was formerly fen 
also, almost half of the country would have originally been included 
in this formation. The existing marshland lies either round small 
lakes or along the course of the streams. Its origin may be 
accounted for in several ways. It was probably derived from a 
series of lakes in a badly drained partially submerged country. 
This may have originated at a period when the surface of the land 
was not so high above the sea and the rivers were consequently 
near their base level, and when the precipitation was greater. The 
level of the land is known to have been lower during early post¬ 
glacial times than to-day, since raised beaches of the “ Littorina 
sea” are found, which were formed in comparatively recent 
Quaternary times. 1 The lakes might also be due to the partial 
solution of the underlying limestone, or to the occurrence of hands 
1 The historical development of the flora of Gothland has been 
studied by Sernander. Studier ofver den Gotldndsha vegetationens 
utvechlingshistona. Ahad. Afh. Uppsala, 1894. In the “ Littorina 
age” of post-glacial time, there was an extension of the sea 
in many parts of West Europe. The Baltic had probably 
been hitherto a fresh water lake (the “ Ancillus Sea ”) but 
now became much more extensive. The lower layers of peat 
in Gothland date from these Ancillus and Littorina periods 
(named after the characteristic molluscs) ; they contain a 
large number of plants, Phragmites being abundant. It is 
likely that the Littorina subsidence came about the end of 
the neolithic period. 
