Botany and Zoology. 151 



Mr. H. C. Sorby had before attributed the cleavage to the effect of such 

 lateral pressure on all the grains or pebbles in the rock, the force making 

 the particles whether of luica or any stones to place their larger diameters 

 in the plane at right angles to the direction of the pressure, that is in the 

 plane of cleavage. lie had appealed to facts iu the slates of "Wales, 

 sho^Ying that "where mica scales were present, they had this position. 

 This cause may contribute to produce lamination, though not appearing 

 to be necessary to the result. 



In the Philosophical Magazine for December last, Rev. S. Ilaughton 

 gives the results of some calculations to ascertain the amount of the 

 pressure which was exerted in cases of the production of slaty cleavage, 

 using as data the degree of distortion or compression of fossils. 



8. The genus Palmotroclds of Emmons^ instituted as a genus of fossil 

 corals. — We have received a note from Prof. Emmons urging several 

 reasons for sustaining his genus Palaeotrochis, and against the view of its 

 being a quartz concretion. The main point presented is the fact of ita 

 form — a double cone with striated sides, the stria3 at right angles to the 

 common base of the cones. 



III. BOTANY AKD ZOOLOGY. 



1. Introduction to Cryptogamic Botany ; by the Rev. J. M, Berkeley^ 

 M.A., F.L.S. With 127 illustrations on wood, drawn by the author. 

 London : H. Bailliere, 185V, pp. 604, 8vo. — This is the first original work 

 of the kind that has been published in the English language. Its only 

 predecessor, the Endlsh translation of Sprengel's Introduction to the 

 Study of Ciyptogamie Plants, appeared half a century ago, and its last 

 edition in the year 1819. A comparison of the two books would be 

 curious enough, so great has been the advance in our knowledge of the 

 lower orders of plants during the interval, and especially within the last 

 I twenty years. 



A work of this kind has long been a desideratum, and before all others 

 would Mr. Berkeley be looked to, as best qualified to supply it. No Brit- 

 ish, and probably no foreign botanist, except Dr. Montague, has so exten- 

 sive and so accurate an acquaintance with the whole range of the lower 

 Gryptogaraous ordei-s, and especially with Mycolog}^ The work likewise 

 indicate a good knowledge of Phaenogaraous botany, and discusses some 

 important general questions with more than ordinary ability and breadth 

 of view. As might be expected, the book before us is an excellent oiie» 

 full of original observations, indispensable to the Cryptogamous student 

 who cannot command a considerable library, and highly interesting to 

 the general botanist. As rcspecte the subject-matter, we can well believe 

 the author's statement, that "an incredible amount of labor has been 

 bestowed upon its preparation, in the examination of herbaria, the con- 

 sultation of authorities, and the verification of facts " It is much to be 

 regretted, candor compels us to add, that some part of this labor was not 

 bestowed upon the arrangement and the style, which, considering the po- 

 sition of the accomplished author, are careless and faulty to an ' incredible* 

 degree. The mere want of arrangement, although a serious defect in au 

 elementary work, is not the worst of faults; and it is rather refreshing to- 

 meet with admirable and original observations in unexpected places. 



