A New Handbook to the Geology oj Ireland. 315 



he wishes to see whether Balliuagappoge or Knockaunavoher is repre- 

 sented in the collection, he may have to search over an extensive series. 



When we attempt to comment on the details of the text, we find the 

 perusal of the book far more interesting than any attempt to criticise it. 

 In a few lines, for instance (p. 17), we have an account of Sir A. Geikie's 

 views on the " conglomerates " of Howth, and Prof. Sollas"s suggestion 

 that the majority of these rocks are breccias ; while, lower down on the 

 same page, the theory of slaty cleavage is introduced in an account of 

 the slates of Co. Wicklow. We notice, by-the-by, that the names of the 

 Irish counties are written throughout the work without the prefix, which 

 is, perhaps, to be regretted from the point of view of geographical preci- 

 sion. An Englishman does not say that Woodstock is in Oxford, or that 

 Whitby is in York; and such a phrase as " isolated localities in Dublin 

 and Wicklow " (p. 18) is, we believe, liable to misconstruction. 



It goes somewhat against the grain to find (pp. 18, 60, &c.) the division 

 " Lower Silurian " merged into the general term " Silurian," although it 

 appears as a separate system in the table on p. 16. Surely this is too 

 great a sacrifice to deceased authorit}-. We note, however, with pleasure 

 that the Old Red Sandstone is accorded (p. 83, &c.) a distinct systematic 

 position, and is not swallowed up, as was once threatened, between the 

 Silurian and the Carboniferous. Even the alleged conformity between 

 the Dingle Beds and the Silurian becomes a dubious matter in the field, 

 and Jukes himself preferred to let his mapping controvert his conclusions, 

 and to state his difficulties most plainly. 



For observers in Co. Dublin, the fine account of the Leinster granite 

 and its flanking masses will have especial interest (pp. 31-35 and 39-40). 

 In the list of minerals (p. 32) we may take exception to the description 

 of apatite as merely "hexagonal phosphate of lime" ; to copper pyrites 

 as " cubic sulphide " of copper, when it is tetragonal, and contains as 

 much iron as copper ; and to kaolin as ''silicate of alumina" only, its 

 mode of formation being outlined without reference to the hydration. 

 Too many names, moreover, seem to us to be used for igneous rocks in 

 general ; the ordinary museum-student — and, for that matter, the most 

 experienced petrologist — may really gain in philosophic knowledge by 

 grouping together such generic names a;s diabase, proterobase, hypcrsthenc' 

 porphyrite, epidioriie, lamprophyre, and kcnantite, under far more simple family- 

 titles, distinguishing the special types by adjectival affixes. This point, 

 however, will always be a source of friction between those to whom the 

 name of a rock-mass comes as a reminder of some microscopic section, 

 and those to whom it seems almost as the echo of an elfin trumpet, borne 

 along all the range of crag and purple moorland. We have evidence that 

 the aspect of the country- itself was often in the minds of the writers of 

 this museum-guide, as, for instance, in the account of the Mweelrea area 

 on p. 45, and the capital description of the limestone country of Co. Clare 

 on p. 87. 



The geographical grouping of the rocks under the several provinces 

 requires some occasional cross-references, which might be obviated by an 

 index such as that which we have suggested. Thus a traveller between 



