THE INSECT ASSOCIATION OF A LOCAL ENVIRONMENTAL COMPLEX. 
39 
Physiography and Topography. 
In so far as the locality of our investigations is representative of the conditions 
which prevail throughout the lower-lying reaches of the Dane valley, it may be 
considered as physiographically typical of the whole area. Terraces of a fairly 
wide sweep; composed of river gravel, extend along the greater part of the valley.* 
Westwards from the North Rode viaduct the river winds from side to side of a 
flat of an average breadth of a quarter of a mile, on each side of which rise hills 
of red marl capped by a few feet of sandy gravel, and the valley shows here and 
there traces of two or three terraces. The river runs in a deep channel cut through 
this old alluvium well down into the red marl below. The pebbles in the gravel 
are of all sizes, up to that of a man’s fist, and there are sometimes beds of sand : 
the gravel is at times stratified, but is oftener just such a rude tumbled mass of 
pebbles and boulders as now lies in the bed of the river ; it has doubtless been 
formed mainly from the waste of .the Drift Sand and Gravel. As this gravel rests 
on red marl without any trace of boulder beds between, it is likely that the valley 
of the Dane has been greatly deepened since the Drift period. From Congleton, 
eight miles to the west, to Holmes Chapel and beyond, on the north-east side of 
the valley, a pair of terraces may be made out, but they have been much cut up 
by river denudation. They soon give place to a broad, well-marked flat about 15 
or 20 feet above the river, with here and there a ledge some 10 feet lower. 
The farmland of the Holmes Chapel Agricultural College stands at about 
225 feet above sea-level, which represents the altitude of Glover’s Meadow, covering 
an area of 1‘633 acres (PI. I ; PI. II, fig. 2). This name has been used throughout 
the paper to designate the grassland situated on the top of the wooded declivity, 
at the bottom of which the Alluvial Pasture of 4'658 acres (PI. I; PL II, fig. l) 
extends along the south side of the River Dane. The Farm Pasture, on which is 
situated the filtering tank of the College sewage system, is 4'09 acres, wheat 
field 6'94 acres, and potato field 5‘86 acres, about one-tenth acre being sown in 
oats and a small strip planted with cabbages as represented in the diagram (PI. I) 
taken from the survey map of the farm. As the study is mainly concerned 
with the two fields, Glover’s and Alluvial, the latter of which is confluent with 
the higher-lying Farm Pasture, the importance of the adjacent fields and woods 
lies in the fact that the crops and trees which they bear supplied numerous species 
of insects which invaded our more limited area and so had to be considered as 
temporary invaders or migratory forms. 
The Alluvial Pasture stands at a height of about 155 feet above sea-level. Its 
surface soil is derived from the Post-Glacial Drift, and consists of alluvium. This 
is in decided contradistinction to the surface soil of Glover’s Meadow, which is 
* Hull, E., and Green, A. H., “The Geology of the Country round Stockport, Macclesfield, Congleton, and 
Leek,” Mem. Geol. Sur. Gt. Brit., London, 1866, p. 80. 
