302 Notices respecting New Books. 



hitely groundless, have often occasioned investigations whith 

 have led to theories founded on truth ; but it will not in the 

 present age He denied that a too ready adoption of systems with- 

 out sufficient facts to support them lias been the bane of science, 

 and operated to retain mankind in a state of ignorance. The 

 facts stated in this paper furnish various '* objections to the com- 

 monly received arrangement" of strata, and "enforce on geo- 

 logists the necessity of drawing their distinctions from real and 

 uot from theoretical [hypothetical] views, and of establishing 

 criteria which are better founded, and which rest on more satis- 

 factory evidence than that produced by the mere apparent or 

 even real superposition of an unstratified aljove a stratified rock." 

 We regret that our limits do not allow us to offer an enumera- 

 tion of the new facts established by Dr. MacCulloch's Sketch of 

 the Mineralogy of Sky; but his " detailed description of the 

 marble of Strath" should be seen by others as well as geologists, 

 were it only for the " oeconomical uses to which it seems appli- 

 cable,' and we therefore give it in his own words: 



" The following varieties are the most remarkable of those 

 which are to be seen in this tract. 

 " 1. Pure white marble, the fracture intermediate between the 



granular and small platy. 

 *' 2. The same with a scarcely discernible shade of gray. 

 " 3. The same with variously disposed veins of gray and black, 

 resembling the connnon veined marble used in architec- 

 tural ornaments. 

 " 4. The same with narrower veins well defined, and often reti- 

 culated with a great semblance of regularity: very orna- 

 mental. 

 *' 5. The same, distinguished, independently of the veins, by a 

 parallel and regular alternation of layers of pure white and 

 grayish white. 

 *' G. White marble variously mottled and veined with gray, yel- 

 low, purple, and light green. This is also a very orna- 

 mental variety. 

 " 7. Marble, exhibiting various mixtures of white, pink, purple, 

 light green, dark green, and black, of a rich sombre 

 effect, and highly ornamental. 

 '' S. White marble, beautifully mottled and veined by yellow 

 transparent serpentine. 

 '' The ornamental coloured marbles here described, scarcely 

 vield in beauty to many of the similarly constituted specimens 

 of ancient marbles, and like many of the marbles of Scotland 

 they will be found to owe their colours to serpentine. This is 

 also the cabc in Gleu Tiltj at Balahulis!)_, and in lona. But the 



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