Feb. 27, 1879] 



NATURE 



383 



ture of Ireland are full of suggestive matter, and will be 

 consulted by all who wish to learn what has been done in 



Irish geology. 



The section which will provoke most criticism is, 

 no doubt, the second — on Metamorphic and Eruptive 

 • Rocks. The author himself hints something to this 

 effect in his preface. There are objections to the termi- 

 nology he has invented, the words themselves being 

 unfortunately selected. For Daubree's term "regional 

 metamorphism " he substitutes nietapepsis, and, speaks of 

 metapeptic rocks. A dyspeptic geologist — and we suppose 

 such beings exist in some number — will shudder at the very 

 sound of these words. Then the old term " contact meta- 

 morphism," long ago so elaborately illustrated by Delesse, 

 is replaced by paroptesis, and its rocks are called par- 

 optetic. Another term, nuthylosis, is applied to a local 

 kind of metamorphism, "due to the introduction and action 

 of chemical substances from without ; " and the rocks 

 affected by it are named methylotic — a word which many 

 a learner will at once surmise to be connected in some 

 way with the methylated spirit he used to spill and smell 

 of in the days of his practical chemistry. 



But accepting these terms, there will be graver objec- 

 tions to some of Mr. Kinahan's metamorphic notions. It 

 is specially unfortunate that he does not give any ade- 

 quate grounds in this volume for enabhng the reader who 

 has not perused his other writings to judge on what de- 

 tailed evidence his conclusions have been based. For 

 example, he treats quartz-rock as one of the intrusive 

 granitic rocks, and distinguishes it from quartzite or 

 quartz- schist. But we have been unable to discover any 

 passage which explains how he could distinguish these 

 rocks, and what are their relative mineralogical and petro- 

 graphical characters. Nay, while in one place he includes 

 quartz-rock among the highly siliceous intrusive granitic 

 rocks, he elsewhere speaks of it as having been again and 

 again deposited by springs connected with volcanic action. 

 Surely he does not wish us to beheve that even a tyro in 

 petrography would confound siliceous sinter with any 

 form of granitic rock ? Again, without giving any data, 

 he speaks of "protrusions of limestone and dolomite." 

 How does he imagine they were protruded ? Were they 

 thrust out as solid masses, or hke the quartz-rock of his 

 springs ? He mentions them in connection with " a sheet 

 of quartz-rock," and speaks elsewhere of having himself 

 observed intrusive quartz-rock Ln many places. It is 

 evident, however, that it would lead to the most hopeless 

 confusion if the term quartz-rock, which has for genera- 

 tions included hardened siliceous sandstones, sometimes 

 even with traces of organisms, were applied also to any 

 member of the granitic family. Mr. Kinahan should 

 invent another name for his intrusive quartz-rock. He 

 has no timidity in names, and might hit upon one quite 

 as euphonious as those already referred to. 



Probably the most valuable part of the book is that 

 which treats of the prehistoric remains. Mr. Kinahan 

 is an authority on crannoges; and the digest therefore 

 which he has given of known facts in this subject, besides 

 its interest to the general reader, will be welcomed by 

 geologists to whom the scattered papers in the Transac- 

 tions of the Irish Societies are not familiar. 



The illustrations are singularly poor, and seem all the 

 more so by contrast with the sketches of the lamented 



Du Noyer, which have made the geology and scenery of 

 Ireland familiar to many eyes all over the world. Could 

 not Mr. Kinahan have availed himself of some of the 

 drawings, published or unpubhshed, of his friend ? Any 

 additional publicity he could have given them would 

 have been another tribute to the memory of a true artist. 

 While the author recognises the debt of gratitude owed 

 by Irish geologists to Griffith and Jukes, there are some 

 names which he passes over in strange silence. Why, 

 for instance, could he find no room for the honoured 

 name of Harkness ? Surely, when he was writing about 

 the metamorphic rocks of Donegal, he might have made 

 grateful allusion to the geologist who, more than any one 

 else, has thrown light upon these rocks. He quotes two 

 or three times an opinion of Prof. Hull only to reject it, 

 and these are all the direct references he deigns to make 

 to the labours of one who has already done and is still 

 doing so much for the cause of Irish geology ; there 

 being not the least allusion anywhere to the previously 

 published volume by that writer. This may have arisen 

 from mere inadvertence, and in that hope we take leave 

 of Mr. Kinahan and his book, wishing for both that 

 appreciation from geological readers which they de- 

 serve. 



OUR BOOK SHELF 



Studies in Comparative Anatomy. No. I. The Skull of 

 the Crocodile. By L. C. MiaU. No. II. Anatomy oj 

 the Indian Elephatit. By L. C. Miall and F. Green- 

 wood. (London : Macmillan and Co., 1878.) 



Prof. Miall has given in the first of these "Studies" a 

 careful and systematic description of the Skull of the 

 Crocodile, his object being to fiu^ish to students a 

 more complete account of the skull in this family of 

 reptiles than is foimd in the usual treatises on the Com- 

 parative Anatomy of the Vertebrata. He commences by 

 giving a general view of the crocodilian skull, and then 

 sketches its mode of development, pointing out at the 

 same time the relation of the cranial nerves to the post- 

 oral clefts and arches. The individual bones of the skull 

 are then described in detail. An elaborate accoxmt is 

 given of the tympanic cavity and of its communications 

 with the several Eustachian passages, which, together 

 with the external auditory meatus, represent the cleft 

 between the mandibular and hyoidean arches. !Mr. 

 Miall gives in an appendix a translation, with annotations, 

 of Rathke's account of the development of the skull of 

 the crocodile. The essay will be of great service to those 

 desirous of acquiring a knowledge of the crocodile's 

 slailL 



In the second of these " Studies " Pro£ MiaU writes, in 

 conjunction with Mr. Greenwood, an account of the 

 anatomy of the muscular, vascular, digestive, and genito- 

 urinary systems of the Indian elephant, together with 

 some observations on the organs of special sense. This 

 essay appeared originally in the Journal of Anatomy and 

 Physiology for 18; 8, and in reprinting it the authors have 

 reproduced the plates and woodcuts employed in illus- 

 trating their description as it appeared in t\i?it Journal. 

 Throughout the essay frequent reference is made to the 

 previous literature of the subject, and the authors point 

 out any discrepancies between their observations and the 

 descriptions of the other anatomists who have examined 

 this species of elephant. The part of this essay which 

 contains the greatest number of new facts is the descrip- 

 tion of the muscular system, which is very carefully done, 

 and forms an important contribution to the myology of 

 this huge animal. 



