50 Origin of the British Flora. 



nothing but thousands of seeds belonging to half a dozen 

 aquatic plants, which were already quite well known. As 

 an example, we may take the flora of the Cromer Forest- 

 bed, which is still a small one, for the deposits belonging 

 to it are parts of a wide-spread alluvial plain, with shallow 

 pools and broads. Yet the collection of the plants has 

 given me ten times the trouble that was needed to obtain 

 a much larger number of species at West Wittering. This 

 latter deposit is of estuarine origin — it therefore contains 

 mingled fresh-water, estuarine, and sea-coast plants ; it is 

 the deposit of a very small stream — the proportion of dry- 

 soil species is therefore exceptionally large, and their seeds 

 are unusually well preserved ; moreover, the stream within 

 a mile crossed the edges of a most varied series of strata, 

 including chalk, stiff clay, loose sand, marl, loam, and 

 gravel — the flora is therefore as good an epitome of that 

 of the surrounding district as could be obtained by the 

 examination of several deposits, each of which only fulfils 

 some of these conditions. It may be added that, while the 

 best fossiliferous deposits in the Forest-bed are commonly 

 stiff clays or peaty-beds, difficult to take to pieces without 

 injury to the fossils, the strata at West Wittering are 

 sandy loams, which, when dried and placed in a sieve in 

 water, quickly fall to pieces and leave the seeds un- 

 injured. 



Deposits like that just mentioned, though giving the 

 best general view of the flora of a district, are unsatisfac- 

 tory in certain respects; for they seldom yield well- 

 preserved leaves, and many species having soft seeds can 

 only be recognised by the leaves. In order to discover 

 leaves of any plants, other than the small tough-leaved 

 Arctic ones, it is commonly necessary to split up laminated 

 lacustrine clays, or masses of bog-iron ore ; but, unfortu- 

 nately, Pleistocene clays are seldom sufficiently firm to 



