3i6 The Irish Naturalist. 



Newcastle and Warrenpoint might expect to find his rocks illustrated in 

 the case styled " Coast of Down " (p. 74) ; whereas they are more conve- 

 niently dealt with under the heading of " The Mourne Mountains." The 

 important questions raised by the igneous rocks of Ulster are remarkably 

 well treated in a summary of some nine pages. 



We hope to hear more of the phonolite of Blackball Head (p. 91), the 

 " Ivernites " of Co. Limerick (p. 93), and other rocks of which Mr. Watts 

 has special knowledge, here modestly passed over. The last thirty- five 

 pages of the guide are devoted to an account of the fossils displayed, pre- 

 faced by an outline of the classification of the animal kingdom. This 

 latter feature seems beside the purpose of the guide, and might have been 

 handed over to the zoological department of the museum, especially as 

 there is no corresponding introduction to mineralogy and petrology in 

 the earlier portion of the book. It is impossible to do justice to the de- 

 tails of animal structure in such limits ; this is apparent in the description 

 of the older and modern types of crinoids (p. 100), of the limbs of trilo- 

 bites (p. 102), and of the pulmonata (p. 105) as "lung-bearing shellfish." 

 In the survey of the special palaeontology of Ireland, the gender of certain 

 specific names is open to correction ; but the information seems to rival 

 the petrological portion in the attention given to recent work. As ex- 

 amples, the Durham concretions are correctly mentioned as "calcite" 

 (p. 109) ; while Pucksia MacHenryi already finds a place as an Irish fossil. 

 An important list of figured and type-specimens in the collection con- 

 cludes this section of the guide. 



Altogether, this little paper-covered volume is a real addition to our 



libraries, and its excellences are likely to be appreciated by the specialist 



even more than by the enquiring visitor. It will now be impossible to 



enter upon research in any Irish county, without referring in the first 



place to what Messrs. McHenry and Watts have thought fit to say upon 



the subject. 



Grenvii,i,E A. J. Coi,E. 



CORRESPONDENCE. 



Quartz, Quartz-rocks, and Quartzltes. 



To the Editors of the Irish Naturalist. 

 Tn a paper recently published by the Royal Irish Academy on "Quartz, 

 Qnartz-rocks, and Quartzites," I notice that Mr. Kinahan quotes some 

 passages from a letter written by me to him on the subject of sinters 

 from Iceland. As his statement, made just before the first quotation, is 

 open to some little misunderstanding, and as I have no copy of the 

 letter, I am compelled to ask him, through you, to publish any statement 

 in my letter, except that which he has already quoted, which has any 

 bearing on the clastic structure of sinters. If he will be good enough 

 to do so, the bearing of the study of sinters on quartzites and quartz- 

 rocks will be a little clearer. 



W. W Watts, 

 Corndon, Worcester-road, Sutton, Surrey. 



