724 MAPPING AS AN ECOLOGICAL INSTRUMENT. 
When preparing to survey a specified area, the scale upon 
which the map is to be charted must receive careful con- 
sideration. If it is desired to indicate much detail, a large 
scale must be used. If the area is extensive the use of this 
large scale has the great disadvantage of making the resulting 
map very unwieldy, so that it has to be reduced to within 
reasonable working limits. Practical experience has shown 
that the better plan is to use at first a relatively small scale, 
such as 1/2500, which is that adopted on many of the ordnance 
survey maps. In this case much of the detail has to be 
eliminated, so that only the salient features of the survey are 
indicated. When once such a general field map of the whole 
area is completed, any number of small maps can be con- 
structed by various methods, showing the details of typical or 
specified areas on as large a scale as may be desirable. 
During the last ten years two ecological surveys have been 
carried out under the direction of Professor F. W. Oliver, of 
University College, London, one at the Bouche d’Erquy, 
Brittany, the other at Blakeney Point, Norfolk. From these 
two sources most of the illustrations for the present paper are 
drawn. 
It is always useful and advisable to glean as much informa- 
tion as possible with regard to the past history of the area 
under consideration. Very frequently old maps and pictures 
are extant, which convey certain ideas, though as a general 
rule the maps at least are most remarkably inaccurate ! In the 
Presidential Address of the late Mr. C. liamond, read to this 
Society in 1907, a series of old maps and pictures of Blakeney 
Point are illustrated. 1 The first map or picture is dated 1586, 
and conveys but a vague idea of the Point, while relative 
distances and positions are stated by Mr. Hamond to be very 
uncertain. The second map, 1690, about 100 years later, is 
much clearer. The pebble stone beach is shown as continuing 
right round the sandhills ; the wall indicated is not now 
evident. The third map was made in 1797, and is supposed to 
l Trans. Norfolk and Norwich Naturalists' Society, Vol. VIII., p. 333. 
