INTRODUCTION XXXVU 



Poferimn polygamum, Valerianella deninta, V. rimosa. Cichorium, Crepis biennis, 

 C. taraxacifolia, Lithospermum arvense, Linaria repens, Orobanche TrifoHum- 

 jyratense, Bromus interruptus, Allium vinea'e, Anihemis arvensis, and Legouzia 

 Even this list does not exhaust the flora of the Chalk. On it is the 

 only locality in the county for Galium sylvestre and for Astragalus danicus. 

 Rosa rubiginosa, R. micrantha, and R. iomenlosa are found, but the Brambles 

 are but scantily represented. Viola hirta is a conspicuous feature in the 

 spring, as are the wood-plants Asperula odoraia and Lamium Galeobdolon. 

 Juniperus, Clematis Vitalba, and Taxus baccata are also characteristic 

 plants. 



Reading Beds. The lowest Tertiary strata found in Berkshire 

 l^elong to the subdivision known as the Woolwich and Beading Beds. 

 The double name was adopted because the character of the deposits of 

 this date in the eastern part of the London Basin is widely different 

 from that which prevails in the west. Our Berkshire representatives 

 conform to what is known as the Beading type. They consist very 

 largely of stiff clay mottled with a great variety of colours, but they 

 also include beds of sharp sand, also variously coloured, and loams. 

 They rest unconformably on the Chalk, and frequently occupy potholes 

 which have been excavated by percolating water in that rock. 



The«e beds once formed an unbroken sheet extending over the whole 

 of the Chalk, and even beyond its present limits, but they have been 

 largely swept away by denudation, and, beyond their main mass, 

 a very large number of outliers testify that they had formerly a much 

 wider range. 



The Beading Beds are found scattered over a large area of Southern 

 Berkshire, the most northern point reached by them being at Let- 

 combe Bowers, where there is a small outlier. Doubtless at one time 

 the whole of the Chalk area was covered' by them, but subsequent 

 denudation has removed them from the greater portion of the northern 

 Chalk. The main mass of the Eocene occupies a trough or synclinal 

 of the Kennet forming a triangular area. This can be traced from 

 the Wiltshire border of the county, near the Shalbourn outlier of 

 Greensand, along the south side of the Kennet as far as Crookham. 

 On the north side of the river they extend as far as Thatcham and 

 Theale, but from Thatcham eastwards the drift gravels quite obscure 

 them. At Shaw, near Newbury, the Beading and Woolwich Beds are 

 52 feet thick. There are a large number of outliers ; over forty are 

 given on the Ordnance Map (No. 13) alone. North of the Kennet, on 

 the western side of the county, is the important outlier of Wickham 

 Heath, which forms a piece of high ground nearly a mile in breadth, 

 and about six miles in length. It is thickly covered with flint gravel ; 

 the small patch east of Elcot is a projecting part of this outlier. Two 

 small outliers at Stanham Green are chiefly yellow sand. Another 



