240 



THE MOLLUSCA OF OUNDLE. 



By the rev. C. E. V. KENDALL. B.A. 



(Read before the Society, February i2tli, igig). 



During the past decade a great deal of valuable work has been done 

 in mapping out in this country the various types of woodland and 

 the associations of plant life on different soils and under varying con- 

 ditions of moisture, shade, and altitude. In this paper it is proposed 

 to deal on ecological lines with the moUusca of a small area in the 

 Eastern Midlands. The moUusca have in their individual life a very 

 small range, so small that they may be described as " spot-bound," 

 and consequently they lend themselves better perhaps to this method 

 of study than any other group of living creatures. It has of course 

 long been known that many species of moUusca have a pronounced 

 preference for certain definite types of habitat, away from which the 

 species is not to be found; but it appears that, by means of careful 

 search and comparison of records, it is possible to define the associa- 

 tion of species which may be found living together in any particular 

 habitat. This work can only be done by degrees, and it is hoped 

 that these notes may be of value to those who are working on 

 similar lines. 



The area dealt with is that lying within a radius of about five miles 

 of Oundle, a small town in the north-eastern part of Northampton- 

 shire. It is a purely inland area, through the midst of which flows 

 the River Nene, a stream of medium size with a good volume of 

 water and a fairly rapid current. There are no extremes of altitude, 

 the country on both sides of the river being of a gently undulating 

 nature, rising at the most to about 300 feet above sea-level ; it is 

 well wooded, extremely so on the western side, where it includes 

 many outlying fragments of the ancient Forest of Rockingham. 



The geological formations are fairly simple in their main outlines, 

 comprising principally the upper strata of the Jurassic System. The 

 higher lands both east and west of the river are wholly Oxford Clay, 

 while nearer the river and at a lower level appear strata of the Oolite, 

 viz., the Cornbrash and the clays and limestones of the Great Oolite. 

 A large section has as a covering a thin mantle of Glacial Drift, 

 usually consisting of a calcareous clay, and so is well adapted to 

 support a large and varied molluscan life. 



In comparison with the complex geographical and geological con- 

 ditions of some districts, the very simplicity of those conditions here 

 is of great value, as it enables one to establish one's conclusions, 

 even if they be limited in number, by the collation of a great number 

 of similar examples. 



