40 



NATURE 



[May 17, 1877 



having any real foundation in fact. For it must not be 

 forgotten that, however certain questions now pending 

 concerning the nomenclature of the Welsh strata may 

 eventually be decided — and these questions of nomen- 

 clature and priority are, after all, of very secondary im- 

 portance—the grand fact first clearly determined by the 

 discoveries of the illustrious Barrande in Bohemia, that 

 there can be distinguished in the series of older Pal.tozoic 

 strata three great divisions, each characterised by a well- 

 defined fauna, is quite independent of these controverted 

 points, and its value cannot be affected in any way by 

 their decision either one way or the other. 



It will be manifest from what we have said above that 

 we regard the present work of I'rof Nicholson as dealing 

 with a subject in connection with which the want of a 

 competent te.\t-book in this country has long been a 

 serious evil ; and of the general accuracy and reliability 

 of the information supplied by this convenient little 

 volume we can also speak in terms of high commendation. 



Prof. Nicholson has wisely availed himself to the fullest 

 extent of woodcut illustrations in aid of his descriptions 

 of the fossil forms ; and the 270 engravings, many of them 

 containing illustrations of a number of different species, 

 will be a great boon to the geological student. Some of 

 these woodcuts now appear for the first time, but others 

 have already done duty in the author's previous writings. 

 We cannot unfortunately award anything like equal praise 

 to all these illustrations, for while some of them are of 

 exquisite truthfulness, detail, and finish, certain others 

 are so coarsely executed and so wanting in character, that 

 it is a marvel to us how so accomplished a naturalist as 

 the author could have ever permitted them to dis- 

 figure his pages. There is one omission in connection 

 with the illustrations, which will greatly detract, we fear, 

 from the value which they would otherwise have for the 

 student, namely, the absence of indications of the number 

 of limes which the scale of the drawings is magnified or 

 reduced from that of the original objects. Every one 

 engaged in teaching is aware what erroneous notions 

 concerning fossil forms are often propagated by want of 

 attention to this detail. 



In his discussion of the characters distinguishing the 

 flora and fauna of each of the great geological periods, 

 Prof Nicholson is usually very clear in his descriptions 

 and happy in his choice of typical forms. The greatest 

 danger which besets the writer of such a work as the 

 present is that of overwhelming the student with masses 

 of detail, unrelieved by those broader generalisations 

 which may serve to aid his memory in grouping the facts 

 about convenient centres. Had Prof Nicholson in the 

 present work prefaced each of his descriptions of the 

 great geological periods with a succinct statement of its 

 leading pateontological characteristics, and also furnished 

 similar summaries for the greater epochs, we cannot but 

 think that the work would have been far better adapted 

 to the wants of the student, and at the same time its 

 suitability for general readers would have been in no wise 

 impaired. 



The references to authorities at the end of the chapters 

 will be found useful by all classes of readers, and the 

 general remarks on the " Principles of Paheontology " 

 with which the work opens will sufficiently prepare those 

 who may be totally unacquainted even with the funda- 



mental facts of geological science for a profitable perusal 

 of the succeeding chapters. The work before us con- 

 stitutes a popular exposition and summary of the facts 

 of palceontology, suitably arranged for beginners ; but 

 as a text-book for the more advanced student of the 

 science, it still leaves much io be desired. We search 

 it in vain, for example, for information on many im- 

 portant questions, such as the classification of the mul- 

 tifarious forms grouped under the name of Aminoiiihs, 

 and we sometimes find obsolete names employed for 

 certain genera and species. There are certain obvious 

 errors and omissions which will doubtless be corrected 

 and supplied in a subsequent edition of the work — such, 

 for example, as the table of Cambrian strata on p. 79, 

 and the absence of all notice of the remarkable Devonian 

 fossil, Calceola sandalina. 



As a compact and popularly written introduction to a 

 very important department of science, Prof. NichoUon's 

 new work may be safely recommended ; and it is well 

 worthy to take its place among that series of useful ' 

 manuals for which we are already indebted to its indus- 

 trious author. 



OUR BOOK SHELF 



Gi'olo'^ical Survey of Canada. Report of Proi^ress for 

 1874-75. Alfred R. C. Selwyn, F.R..S., F.G.S.,'Dircctor. 

 (Published by Authority of Parliament, 1S76.) 



Although IVIr. Selwyn, like his predecessor, Sir William 

 Logan, has the highest possible ideal of the importance 

 of pure geological mapping, the necessity for the rapid 

 exploration of a vast unsurveyed new land simultaneously 

 with the development of rich coalfields, compels him to 

 employ two very different systems of working. With a 

 staff of only ten geologists, two-thirds of whose time is 

 engrossed by topographical preliminaries, the usefulness 

 of the survey as a whole must depend to a great extent 

 on the judicious determination of the degree of import- 

 ance attached to the details of its various parts. Accord- 

 ingly, Mr. Selwyn has confined the detailed mapping to 

 the settled eastern sea-board, carrying on at the same 

 time reconnaissances in the central and western regions, 

 where complete maps will not be demanded for some 

 time to come. 



During the past year Mr. Selwyn has been able, in 

 addition to his administrative duties, to overtake some 

 field-work, chiefly among the paheozoic rocks of New 

 Brunswick and the coalfields of Cumberland and Sydney. 

 The Report contains two geological maps of portions of 

 the Cape Breton Coalfield, by Messrs. Robb and Fletcher, 

 exhibiting all the completeness of the British coalfield 

 maps. 



Mr. R. W. Ells furnishes a map and report on the 

 hematite ores of Carleton County, New Brunswick. The 

 ore appears to occur in veins along the stiike of highly- 

 inclined Silurian rocks. 



Mr. Henry G. Vennor has been surveying in the 

 Laurentian region of Frontenac and Lanark Counties, 

 and embodies the results of his labours in a map and 

 report. It appears that apatite mining in this district has 

 recently ceased to be a profitable industry. Mr. Vennor 

 sees the cause of failure in the injudicious and costly 

 manner in which the mining was carried on. Iron ore 

 (magnetite) occurs at Eagle Lake in a bedded form, 

 associated with hornblendic and dioritic rocks. 



Mr. Robert Bell and Mr. Joseph Spencer describe the 

 country between the head-waters of the Assineboine 

 River and Lakes Manitoba and Winnepegosis. During 

 a rapid survey of this little-known tract, they recorded the 

 occurrence of Laurentian schists and rocks of Huronian, 



