124 



NATURE 



[Dec. 6, 1888 



village embosomed in woods, with its picturesque church 

 tower, surrounded by fertile and well-tilled land. Such 

 an experience is obtained by the traveller who passes over 

 the downs from Marlborough to Avebury or Wooton 

 Basset, from Heytesbury to Chittern or Imber, from 

 Warminster over Battlesbury, and the projecting spur of 

 Bratton Castle to Steeple and Prood Ashton, on their 

 picturesque hills. 



" The part of the county lying north and west of the 

 chalk plateau is of a different character. It is the plain 

 country, as the other is the hill country of Wiltshire. 

 They have been called 'the cheese' and 'the chalk.' 

 This part includes, in the north, the country drained by 

 the Thames and its affluent the Cole, and on the west 

 that drained by the Bristol Avon. It consists of various 

 geological strata, but chiefly of Oxford clay, a band of 

 which, with an average breadth of nearly five miles, 

 traverses this part of the county from north-east to 

 south-west. Viewed from the outer edge, of the chalk 

 escarpment, this region presents the appearance of a vast, 

 well-wooded, and fertile plain, bounded in the far distance 

 by the hill-ranges of the adjoining counties of Gloucester 

 and Somerset. The outer slope of the chalk plateau de- 

 scends a hundred feet or so, its steep sides covered with 

 turf or clothed with hanging wood, and then slopes gently 

 down to the level. Here is a land of pasture-fields and 

 hedges, overshadowed everywhere by elms, growing 

 mostly in the stiff clay soil that overlies the Kimmeridge 

 clay and Coral Rag. Beyond the level, in front, rises a 

 line of hills of the Coral Rag formation. These hills 

 again descend, with an abrupt slope, into the valley (or 

 plain) through which the Avon flows. The most pictur- 

 esque scenery is found on the outer slopes of the hills. 

 The plain, though often finely wooded, is somewhat tame, 

 though its gentle hills and dales are not wanting in a 

 beauty of their own." 



What is said in the introductory chapter about the 

 climate of the county is not satisfactory. Mr. Sowerby 

 sums it up as follows : — 



"On the whole, Wiltshire has probably the most elevated 

 surface of any English county. This gives it certain 

 peculiarities of climate. Its average mean summer tem- 

 perature is higher, its mean winter temperature lower, than 

 those of any other English county." 



In the Report issued by the Royal Horticultural Society, 

 edited by the Rev. George Henslow, on the effect on 

 garden plants of the severe winters of 1879-80 and 

 1880-81, full details are given for the county of the plants 

 that were injured and uninjured. Taking what is there 

 stated in connection with the full details about the native 

 vegetation of the county which are given in the body of 

 the present work, it is quite clear that the whole of the 

 county belongs to the warmest of Watson's six climatic 

 zones, the Inferagrarian, of which Clematis Vitaiba, 

 Viburnum Latitana, and Ruscus aculeatus, are three out 

 of many characteristic plants. The Inferagrarian and 

 Midagrarian zones are represented in England at sea- 

 level ; and two others, the Superagrarian and Inferarctic, 

 in the hill-country of the North of England ; the two 

 coldest of the six, the Midarctic and Superarctic, being 

 reached Only amongst the higher mountains of the Scotch 

 Highlands. So far as one can judge from the botanical 

 point of view, Kent, Sussex, Surrey, Hampshire, and 

 Wilts stand substantially on the same level as regards 

 climate, and cover the whole extent of Watson's In- 

 feragrarian zone, without reaching into the Midagrarian. 

 Mr. Preston is an experienced climatologist and pheno- 

 logist, and no doubt is quite aware that such is the case ; 



but nowhere in the present work can we find a clear 

 explanation of the true state of the case, which from the 

 point of view of botanical geography is all-important. 



Besides the introductory sketch of the physical geo- 

 graphy of the county by Mr. Sowerby, and the chapter on 

 its temperature and rainfall, there is one on its geology, 

 with a table of the twenty strata represented in the county 

 twelve of which belong to the Oolitic series, four to the 

 Cretaceous, and four to the Tertiary. Mr. G. S. Boulger 

 contributes a sketch of its drainage, on which Mr. Preston 

 founds eleven districts, under which he classifies the 

 localities of the rarer plants. Two of these drain into the 

 Severn, two into the Thames, and the other seven into the 

 English Channel. Out of the 500 pages, 430 are occupied 

 with a catalogue of the flowering plants of the county, 

 with such detailed localities for the rarities as have been 

 noted. Great pains seems to have been taken to identify 

 the species, and to trace out their dispersion through the 

 different districts. The eighth edition of the " London 

 Catalogue " is followed as a standard of nomencla- 

 ture ; and out of the 1760 species there registered 

 for the whole of Britain, 849 have been found in Wilt- 

 shire. Of these about 50 are marked as introduced, 

 and at least 50 more are reckoned as varieties in Watson' s 

 " Cybele," where the number of wild British plants, in- 

 cluding ferns, is estimated at 1425. Of these 1425 species, 

 530 are spread over the whole of Britain, 600 scarcely 

 reach into Scotland, 200 are characteristically boreal 

 types, and 77 too local to be classified. Wiltshire yields 

 two plants which are not known elsewhere in Britain 

 — Cnicus tuberosus and Carex to7nentosa — both widely 

 spread on the Continent. Out of 600 austral types, 127 

 are characteristically eastern in England. These are 

 mostly plants that prefer chalk and limestone, and are 

 well represented in the county. Add 30 for ferns, and 

 780 species for Wiltshire will be about the number on 

 Watson's scale of reckoning, and compares properly with 

 the figures as given in tables on pp. 371-81, and elsewhere 

 in the fourth volume of the " Cybele." This is a smaller 

 number than the plants of Kent, Surrey, and Hants, and 

 about on a par with Dorsetshire and Hertfordshire. In all 

 these counties the boreal element of the British flora is sub- 

 stantially eliminated. The special deficiency or unusual 

 rarity in Wilts is of the plants of sandy heatherland, 

 such as the foxglove, Ulex eiiropceus, the fruticose Rubi, 

 and many of the Trifolia, and such grasses as Aira pracox, 

 Deschampsia flexuosa, and Nardiis strict a. Altogether 

 the book is one which no one who is interested in the 

 distribution of British plants can afford to neglect. 



J. G. Baker. 



MR. DODGSON ON PARALLELS. 

 Curiosa Mathematica. . Part I. A New Theory of 



Parallels. By Charles L. Dodgson, M.A. (London : 



Macmillan and Co., 1888.) 

 ''T^HIS small book came into the world a little too soon 

 •L or a little too late for our comfort. It was offered 

 to us for notice in mid-vacation, and thinking we should 

 find something amusing, we incontinently accepted the 

 offer. We found some amusement, for, contrary to the 

 author's experience, we read the preface, which is rather 

 drawn out, but here and there is brightened by a quaint 



