A HISTORY OF BUCKINGHAMSHIRE 



districts, and in almost every case the delimitation of the districts is made 

 by adopting the different drainage areas of the smaller streams, or by 

 dividing the larger into two or more parts. By this means, it is con- 

 tended, more valuable scientific results are obtained than if an artificial 

 system were chosen, or one based upon the geological divisions, or even 

 one in which the divisions were made to represent the various soils. 

 The objection to the plan based upon the geological strata is that so much 

 of the area is obscured by surface deposits, which, as we have seen, mask 

 the character of the strata underneath ; and although in my opinion apian 

 in which the surface soil itself were used to determine the standard would 

 be more valuable, it is quite true that our knowledge of the subject is not 

 yet sufficiently perfected to make it available. The plan adopted here is 

 therefore one based upon the river drainage, notwithstanding the difficulty 

 that sometimes is felt in the separation of portions of the country where 

 the water-parting is obscure, and the more serious objection which is 

 experienced when, as in the case of the Ouzel or Thame, which run 

 transversely to the geological strata, each subdivision will contain several 

 different strata. Moreover, instead of a more or less uniform scenic 

 effect and a fairly uniform vegetation, which would be the case were a 

 stratum such as the Oxford Clay selected, it is obvious we shall in such 

 an instance as that of the Thame have all the varying effects, which 

 different altitudes and soils give to the districts traversed by that stream in 

 its course from its origin in the Chalk hills of Wendover or the Green- 

 sand of Brill through the clays to the river Thames. On the contrary 

 in choosing this plan we keep in harmony with the arrangement adopted 

 in works on the botany of the bordering counties, and the student of 

 plant distribution will be enabled to investigate more easily the flora of 

 the smaller river basins of the midlands. 



Unlike Berkshire, which is wholly contained in the Thames basin, 

 Buckinghamshire has two important river systems, those of the Ouse and 

 the Thames. These therefore form our two great divisions, but the area 

 drained by the Ouse is capable of being further sub-divided into two 

 portions, namely that drained by the Ouse itself and that drained by its 

 tributary the Ouzel. In eliminating the country drained by the latter 

 stream we shall include in the Ouse district proper the country on the 

 Liassic and Oolitic strata. These strata are found also in those portions 

 of the bordering counties which are also in the Ouse drainage. The 

 country drained by the Ouzel is much more varied in its geological 

 character. 



i. THE OUSE DISTRICT 



The district No. I drained by the Ouse has its counterpart in district No. 3 of my 

 Northamptonshire Flora and in district No. 2 of my Oxfordshire Flora. Roughly speaking its 

 configuration is as follows : The Ouse rises at Ousewell near Brackley, and leaves our county 

 near Olney. About a mile from the pleasant town of Brackley the Ouse forms the county 

 boundary of Oxfordshire as far as to Water Stratford, where the line of delimitation from the 

 Cherwell or rather the Ray drainage of Oxfordshire is a line drawn along the Roman road to 

 Newton Purcell, then across country to Goddington, crossing the London and North-Western 

 Railway near Marsh Gibbon station, passing by Calvert station on the Great Central Railway 



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