June 25, 1891] 



NATURE 



72> 



of the Upper Pebble-beds are more than 1300 feet thick, 

 and that they are highly charged with water. This thick- 

 ness is altogether without precedent, and Liverpool is to 

 be congratulated upon being built upon so great a thick- 

 ness of water-bearing Triassic rocks. Mr. Morton, should 

 the work reach another edition, would do well to deal at 

 greater length with the water-supply available from the 

 Triassic strata. Mr. Boult has tabulated the well-sections, 

 and all students of the geology of Liverpool would do 

 well to examine his valuable tables. 



We would call special attention to Mr. Morion's section 

 —unfortunately, the work is not divided into chapters— 

 on the origin of the estuary of the Mersey. While the 

 river has been draining its present watershed from a 

 period far more remote than the Pleistocene age, he holds 

 that the estuarine portion is comparatively modern, dating 

 probably not further back than post-Roman times. It 

 would not, he argues, following Sir James Picton, have 

 been neglected by the Romans, if it had then " presented 

 the copious body of water which it does at the present 

 day." There is no evidence that they did neglect it. The 

 Manchester Ship Canal works have revealed the exist- 

 ence of Roman remains, probably the Veratinum of the 

 anonymous geographer of Ravenna, on the banks of the 

 Mersey close to Warrington, andMancunium (Manchester) 

 is on one of its tributaries. They used it, as they used all 

 the rivers of Britain, for their own ends. Deva (Chester), 

 the great port, and military centre of the north-west, was 

 not far off, and amply sufficient for the western trade at a 

 time when there were no ports in Ireland. The com- 

 mercial importance of the Mersey is solely due to the 

 trade with the New World. There was no reason why 

 the Romans should have paid special attention to the 

 estuary of the Mersey ; and it was outside the system of I 

 their roads. Nor can the date, 1279, of the great inroad 

 of the sea over the Stanlow Marshes, by which the 

 Abbey of Stanlow, built upon a rock only 28'5 feet above 

 O.D., lost much of its land, be taken as evidence of the 

 modern formation of the estuary. The river swings to 

 and fro at the present time, depositing silt here, and 

 carrying away its banks there. In our opinioft, there- 

 fore, the post-Roman origin of the Mersey is not proved. 

 It is still less likely that it is the result of a local sub- 

 mergence, which has not affected Warrington and the 

 adjacent area of Chester. As the evidence stands, the 

 date of the estuary of the Mersey belongs to the same 

 remote prehistoric period as the estuary of the Thames 

 and of the Humber — certainly after the time of the boulder 

 clays, and probably long before there were any written 

 records in Britain. All three are later than the time of 

 the submarine forest which, on the west of Britain, 

 afforded shelter, not merely to our Neolithic ancestors, 

 but to their domestic animals, such as the small short- 

 horn {Bos longifrons), the goat, and the dog. 



W. Boyd Dawkins. 



OUR BOOK SHELF. 



Les Microbes, les Ferments, et ses Moisissures. Par le 

 Dr. E. L. Trouessart. Deuxieme Edition. Bibliotheque 

 Scientifique Internationale. (Paris, 1891.) 

 This is not only an enlargement but a distinct improve- 

 ment on the first edition. Chapters i. and ii., as in the 



NO. I I 30, VOL. 44] 



first edition, give an excellent though short account of 

 the morphology and physiology of fungi and of yeast. 

 Although chapter iii. (on bacteria) is enlarged, we do not 

 think it is sufficiently up to date ; thus, for instance, on 

 pp. 74 and 75, the author questions the existence of true 

 flagella in bacteria, and states that their motility is 

 essentially different from that of flagellate infusoria. 

 Again, in the section in which putrid decomposition is 

 described no mention is made of the entire tribe of 

 Proteus, the essential microbe of putrefaction. 



Chapters iv. and v. (pathogenic bacteria) are consider- 

 ably enlarged, both as to text and illustrations. The rest 

 of the book, chapters vi.-ix., does not differ in any essential 

 respect from its predecessor. 



On the whole, the book is very commendable as a con- 

 cise text-book, well written and copiously illustrated, and 

 as such deserves a high place in the literature of the 

 subject. 



Botanical Wall Diagrams. Size 31 i inches by 24 inches, 

 printed in colours. (London : Society for Promoting 

 Christian Knowledge, 1891.) 



A FIRST instalment of six of these diagrams is now pub- 

 lished. The plants illustrated so far are : common elder, 

 deadly nightshade, scarlet runner, hop, Virginia tobacco, 

 and wild camomile. We do not know on what prin- 

 ciple the selection has been made. It is rather a pity 

 that, out of so small a number, two (deadly nightshade 

 and tobacco) belong to the same natural order, and 

 show no very essential structural differences. In time 

 we hope that all the important orders will be re- 

 presented. The drawings (executed by Engleder, of 

 Munich) are quite artistic, and the colouring excellent. 

 The diagrams are thus very pleasing as pictures, and at 

 the sa ne time the botanical details are correct. 



If the series is continued as well as it has been begun, 

 it ought to be a very useful help in the elementary 

 systematic teaching of botany. D. H. S. 



Chambers's Encyclopedia. New Edition. Vol. VII. 

 (London and Edinburgh : W. and R. Chambers, 

 Limited, 1891.) 



No one who has had occasion to refer to the new edition 

 of Chambers's " Encyclopaedia" can have failed to appre- 

 ciate the care and ability with which it is being prepared. 

 The editor has been fortunate enough to secure the co- 

 operation of many eminent writers, and the information 

 given in the various articles, speaking generally, is well 

 up to date and presented in the way most likely to be 

 convenient for students. We are here concerned only 

 with the papers on scientific subjects, and these, in the 

 present as in the preceding volumes, are in every way 

 worthy of the place which has been assigned to them in 

 the scheme of the work as a whole. Prof. P. G. Tait 

 contributes a short but masterly paper on matter, and 

 Dr. Buchan gives a clear and interesting account of 

 meteorology. The esseniial facts about the Mediterra- 

 nean are compressed into very small space by Dr. John 

 Murray, who also writes on the Pacific. Prof. James 

 Geikie deals with mountains and palaeontology, and Dr. 

 Alfred Daniell has a good popular article on optics, de- 

 voted mainly to the history of optical science. In an 

 article on man, Mr. J. Arthur Thomson states very well 

 some of the problems relating to human characteristics, 

 the origin or descent of man, and the antiquity of the 

 race ; and the same writer sketches the career of Pasteur, 

 and treats of mammals and parasites. Mimicry forms 

 the subject of an excellent paper by Mr. E. B. Poulton. 

 Of course, no subject is treated exhaustively, but the 

 information given, so far as it goes, is sound, and ample 

 enough for the purposes for which an encyclopaedia is 

 usually consulted. 



