178 Reid.— Notes on the Geological History 
obtained, only those are included that date from a period 
previous to the Roman occupation. This limit was fixed on 
the ground that the Roman invasion and the constant going 
to and fro which followed it, must have greatly assisted the 
spread of weeds of cultivation. Of course many weeds of 
cultivation must have come in at an earlier period, when 
cereals were first introduced, but nearly all the deposits from 
which plants have been examined, seem to be of a much more 
ancient date. The newest ‘ submerged forest 5 is probably the 
most modern deposit from which material has been obtained, 
and this submergence dates fully 3000 years since. 
To the officers of the botanical department of the British 
Museum, especially to Mr. Carruthers and Mr. Ridley, I am 
indebted for much assistance in the determination of many of 
the more obscure fossils. The specimens being usually only 
seeds, or the hard parts of the fruit, often strangely altered in 
decay, this has been a very difficult task. The specific 
determination is comparatively easy, but it is sometimes very 
difficult to obtain a first clue in the form of an ordinal or 
generic character, very similar seeds sometimes occurring 
in several different orders — e.g. Caryophylleae and Chenopo- 
diaceae. Mr. Carruthers has kindly undertaken the deter- 
mination of the Grasses, so the species of that order are given 
on his authority. 
Specimens have been received from so many sources, that 
it is impossible here to mention all of them. The most 
important contributions were those from Mr. Jas. Bennie, of 
the Geological Survey of Scotland, who has most industriously 
collected the seeds and other fossils from a number of Scotch 
Pleistocene deposits. These specimens are all preserved in 
the collection of the Geological Survey in Edinburgh 1 . 
From other Scotch localities I have received specimens 
from Messrs. David Robertson, J. C. Howden, Robert Craig, 
and Thomas Scott, and also from the Hunterian Museum at 
Glasgow. 
1 By permission of the Director-General I have been enabled to make use of the 
material in the preparation of these notes. 
