184 Reid —Notes on the Geological History 
Still older, and beneath the whole of the glacial and arctic 
deposits, we find the preglacial ‘ Cromer Forest-bed/ with elm, 
beech, oak, pine, and spruce. This flora has already been 
described 1 , though I have taken the opportunity to bring the 
account up to date, and to make a few necessary corrections. 
In the flora of the Cromer Forest-bed, we find for the first 
time a marked admixture of species no longer found in 
Britain, and also a certain number which there is every reason 
to believe are now entirely extinct, though, in the absence of 
generic or ordinal characters, I do not propose to describe 
them, or give them new names. 
This oldest representative of the living flora of Britain is 
associated with a number of large mammals, most of them 
extinct, and many characteristic of the Newer Pliocene 
period. Many of the mollusca are also extinct. 
Unfortunately, at this interesting point of our enquiry we 
are stopped by the imperfection of the geological record, 
which is so great that not a single recognisable plant has been 
obtained from any deposit in Britain lying between the 
Upper Pliocene and the Middle Oligocene 2 . When plants are 
again met with the flora has a sub-tropical character, and is 
quite unlike that now found in Britain. 
DICOTYLEDONS. 
Thalictrum minus, Linn. 
Numerous very acute achenes of Thalictrum have been 
formerly referred to this species. They may, however, belong 
to the sharp-fruited variety of T. fiavum . Horizon — Cromer 
Forest-bed. Localities — Sidestrand and Mundesley (C.R.). 
Thalictrum flavum, Linn. 
The small blunt achenes of this species are very common in 
the preglacial beds. Horizon — Cromer Forest-bed. Localities 
— Sidestrand, Mundesley, Ostend, aud Pakefield (C.R.), 
1 Trans. Norfolk Nat. Soc. vol. iv. p. 189. 
2 The so-called Miocene Floras of Bovey Tracey and Mull, according to Mr. 
Gardner, are probably of Eocene age. 
