GEOLOGICAL COLLECTIONS. 
103 
and only used for consultation and reference by duly accredited 
students.* 
In some parts of the Museum the reserve collections are 
contained in drawers beneath the cases in which the corre- 
sponding exhibited portion is placed. This applies princi- 
pally to the fossil specimens, the shells, and the minerals. 
The reserve birds and insects have special rooms devoted to 
them, and the extensive series of reptiles, fishes, and other 
animals preserved in spirit is kept, for the purposes of 
safety, in a separate building behind the Museum. In the 
Botanical Department the reserve collections are kept as 
usual in the well-known form of an Herbarium, or HorfAis 
siccus. 
The great bulk of the specimens being arranged in these Suppiemen- 
three series, supplementary collections for facilitating the study [^Q^Jg^^^^^" 
of the distribution of animals and plants, and perhaps also of 
minerals, in space and in time would be advantageous. The first, 
constituting a geographical series, might show by illustrative 
examples the leading characteristics of the fauna and flora 
of each great region of the earth's surface; the second, or 
geological series, would give examples of the fossil remains 
found most abundantly in each formation, arranged so far as 
may be in chronological order. 
The only attempt hitherto made at exhibiting a geographical Geographical, 
series in the Museum is the collection of terrestrial and fresh- 
water vertebrated animals of the British Isles, arranged in the 
pavilion at the west end of the bird gallery. It would be 
difficult in the present building to find room for other geo- 
graphical collections, however interesting and instructive. 
With regard to geological collections, although the specimens Geological, 
in the department so called are mainly arranged not geologi- 
cally, or according to stratigraphical position, but according 
to their natural affinities, yet, in many cases, it has been 
found convenient to adopt a mixed arrangement, the specimens 
within each large natural group being classified according 
to the sequence in age of the strata in which they were 
found. Such an arrangement, however, is only applicable to 
the fossils of a particular region, owing to the difficulties in 
* For conditions as to admission and regulation, see p. 123. 
