MR. W. A. NICHOLSON' ON BOTANY OF SUTTON. 279 
mariscus, etc., and is estimated at the rapid growth of a foot 
in twenty years.” 
It will be of interest to compare this estimate of the rate of 
growth of the peat, with that obtained by the late Rev. L. 
Jenyns (quoted by the late Professor Babington) as to the 
rate of its growth in the Fenland, at Isleham. He gave it as 
the turf-cutters’ opinion that “ before the present more perfect 
drainage of the Fen (Isleham) the turf grew at the rate of 
about twenty inches in sixteen years.” This is a little more 
than double the rate just given for Catfield. Allowing for 
difference of drainage, it seems probable that the late Mr. 
Gunn’s estimate was not very far wrong. 
Schimper divides moors into two classes, viz., high-moor 
and meadow-moor, the former being poor in lime, the latter 
rich in lime. Accepting this division, our marshes would 
come under his description of meadow-moor. He goes on to 
say, “ the humates are less plentiful in the water from meadow- 
moors because their humus acids form insoluble compounds 
with lime.” 
The subject of the formation of humic acids, and of the {)eat 
is one of great interest, and presents many, apparently as yet, 
unsolved problems. The term “ humic acid ” is frequently used 
in discussions on soils, etc., but it seems a very vague one. 
As far as I can gather, it has no strict definition, and there 
is certainly no formula for it. However, I am informed, on 
good authority, that there are no acid waters in Norfolk, 
owing to the large quantity of alkalis present. The above 
remarks may seem somewhat of a digression, but the subject 
has important bearings on the Flora, which I hope will be 
worked out, in the future. 
Amongst the chief constituents of the marsh flora, as distinct 
from the aquatic, are the following : — 
Caltha palustris, L. 
Lychnis Flos-cuculi, L. 
Lotus uliginosus, Schkuhr. 
Spir.ea Ui.maria, L. 
POTENTILLA PALUSTRIS, Scop. 
PARNASSIA PALUSTRIS, L. 
