Deposits containing Fossil Plants. 49 
wise stated, I have myself determined the plants included 
in the lists. 
Various points have to be taken into consideration if 
we desire to avoid failure or useless labour in our search 
for seeds or leaves in a determinable state. The deposits 
most likely to yield satisfactory results are not such as 
one would at first sight select as best for the purpose. 
On consideration, it will readily be understood that a 
wide-spread peat-moss will yield little but remains of bog- 
plants; an extensive lacustrine deposit will contain few 
but aquatic species; a broad alluvial flat may only pre- 
serve plants of the marsh and wet meadow. The work of 
collecting at best is very laborious, and, in order to obtain 
with the least amount of trouble an insight into the fossil 
botany of any particular period or district, it is best, where 
practicable, to select for examination the deposits of a 
small stream which flowed through a varied country. 
These will yield not only seeds of the aquatic and marsh 
plants that lived on the spot, but also of a variety of dry- 
soil plants and trees which grew on sandy or rocky banks 
overhanging the channel. They will also yield seeds of 
numerous species which grew somewhat further away, and 
were brought by birds and dropped from the overhanging 
boughs; and will contain winged seeds transported by the 
wind. 
It may be thought that plants of all these descrip- 
tions will be found in a lake or peat-bog, and no doubt it 
is so; but they will be so rare, and mixed with so large a 
proportion of seeds belonging to some few aquatic plants, 
that the time spent in searching for them will be largely 
increased. I speak of this from personal experience ; for, 
through an imperfect appreciation of this difficulty, much 
time was lost in my earlier work, and samples of clay, 
collected and washed with great labour, often yielded 
B 
