Notices respecting New Books. 309 



syenitic and trap veins which traverse it, as I have before men- 

 tioned, but which however produce no chanc;e in its chemical 

 composition, nor any other effect than that of induration. This 

 addition of price to the current charge of working is sufficient in 

 the harder specimens to counterbalance in a great degree the su- 

 perior cheapness of the material, and the advantages derived from 

 lower freight duty and insurance. Such are the difficulties which 

 oppose the introduction of the most perfect marble which has 

 yet been found in Britain, difficulties which, slight as they are, 

 ought, together with the prevalence of established habits and of 

 a coinrriercial routine, to check the extravagant hopes which 

 have been entertained in this country of su[)erseding by its own 

 produce the importation of foreign statuary marble. But it will 

 not be rendering justice to the marble of Sky if I do not add, 

 that it possesses a property not found in that of Carrara, and 

 one of considerable importance, at least in small sculptures. 

 This is, that compactness of texture by which it resists the bruise 

 which so often takes place in marble at the point where the 

 chisel stops, an effect known to sculptors by the technical term 

 stunning, and of which the result is a disagreeable opaque white 

 :Tiark, generally in the very place where tlie deepest shadow is 

 wanted. 



*' I have little to add respecting the marble of Glen Tilt, as I 

 have spoken of it in another place. Except the some\vhat larger 

 size of its grain, it is scarcely to be distinguished from the Pen- 

 telic: in colour it is precisely similar ; but as the character and 

 defects of the Pentelic, which I have already given, are equally 

 applicable to this variety, we may fairly abaiidou all hope of ren^ 

 dering it useful in the art of sculpture " 



Mr. Phillips's paper On the Oxyd of Uranium, and his drawings 

 of the varieties of the primitive crystal and of its various modifi- 

 cations, forty-seven in number, made from well defined crystals 

 found on specimens from various mines in Cornwall, exhibit a 

 ♦degree of patient and minute and accurate investigation of which 

 but few would be found capable. 



Dr. Berger's and Mr. Conybeare's papers on Ireland, with 

 the accompanying maps and sections, are most elaborate and 

 highly interesting. Plate 9 shows in a very satisfactory manner 

 the geological connexion between the W. of Scotland and the 

 NE. of Ireland. Some facts cont'.ected with the courses of cer- 

 tain basaltic or whin dykes are remarkable. The chalk, which 

 is frequently traversed by them often undergoes a remarkable 

 alteration near the point of contact. This change extends eight 

 or ten feet from the dyke. Next to it the chalk is changed into 

 a dark brown crystalline limestone, the crystals running in flakes 



U3 as 



