A HISTORY OF BERKSHIRE 



of the main outcrop a small outlier is found at the base of Riever Hill, 

 on which the village of Shalbourn is built. The richer and more fertile 

 country afforded by this formation is plainly shown from the high chalk 

 hills of Walbury Camp and the White Horse. The mouse-tail (Myosurus 

 minimus), the hone-wort (Corum segetum) and the grass Bromus interruptus 

 are found on it, and it gives the most northerly home in the county 

 for the water dropwort (QLnanthe crocata). In the streams which issue 

 from the base of the chalk escarpment a pond-weed (Potamogeton densuni) 

 is a prominent feature. The presence of calcareous matter in the soil 

 is shown by the occurrence of such eminently gypsophilous plants as 

 the traveller's joy (Clematis), the candy-tuft (Iberis amara), the grass Bromus 

 erectus, the striped toadflax (Linaria repens), and the thistle (Cnicus elio- 

 phorus. On the Upper Greensand hops are cultivated in small quantity 

 near Didcot, and there are very extensive orchards of plums, cherries 

 and other fruit. 



THE CHALK, like the last two formations, extends right across the 

 county from i o to 12 miles broad, and rises above the vale of Berks in 

 a long graceful escarpment, forming by far the most striking physical 

 feature in the county. This escarpment is indented by numerous narrow 

 winding valleys, most of which are dry, and as viewed from the vale of 

 the White Horse it presents the appearance of a long alternation of bays 

 and promontories, which give it a striking resemblance to a coast-line, 

 but there can be no doubt that its outlines are the product of subaerial 

 denudation and not of marine action. The Dorchester or Wittenham 

 Clumps are two outliers of the chalk on the upper greensand, and 

 Windsor Castle is built on an inlying boss. In addition to the main 

 mass of the Chalk there is a second area to the south of the Kennet, but 

 this, although apparently distinct, is really conterminous with the Chalk 

 of the central plateau, the beds of which, in their gentle southern slope, 

 dip under the tertiaries of the Kennet valley to reappear at a more 

 abrupt angle, and then form the line of picturesque hills of which 

 Walbury Camp, 957 feet above the sea level, is the highest point. The 

 chalk is also present in the south-east of the county from Sonning to 

 Maidenhead, but the eminences in this area are capped with London 

 clay. Where chalk actually comes to the surface we find rolling downs 

 overgrown by short turf, which forms excellent pasturage. Over con- 

 siderable extent of county this has been removed, and then the arable 

 fields show great quantities of the yellow flowered mustard (Brassica alba), 

 here called charlock, and four species of fumitory (Fumaria) have been 

 found, Fumaria officinalis, F. parvijiora, F. Vaillantii and F. densiflora, as well 

 as the candy tuft (Iberis amara), the sainfoin (Onobrychis), the chicory 

 (Cichorium), etc. The turf offers in profusion the beautiful blue flowers 

 of the milkwort (Polygala calcarea), the pink flowered squinancy wort 

 (Asperula cynanchica], the blue Canterbury bell (Campanula glomerata], the 

 purple flowered gentians (Gentiana germanica and G. Amarella), and here 

 too the writer was fortunate enough to discover a new hybrid of these 

 species which he has named G. Pamplinii. There are also the field rag- 



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