304 ON THE RED SANDSTONE, MARBLE, 
the masses at a greater depth are greatly more sound, and 
that—as is common in marbles—what occurs as a flaw 
within the influence of the percolating rains and penetrating 
frosts, may exist, removed beyond their reach, as merely a 
streak or vein. I find it stated by Mr. Carmichael, in an elab- 
orate essay on the Limestone Quarries of Scotland, which re- 
ceived the prize of the Highland Society, that no real marble 
has ever been found in this country,—no stone, at least, fitted 
to stand what he terms the three criteria of a true marble, 
viz., susceptibility of a high polish, chemical composition, and 
compact homogeneous structure. He states that Sutherland 
marble leaves three per cent. of residuum when subjected to 
the testing muriatic acid, whereas Carrara marble leaves none ; 
and that every attempt to polish Scotch marbles has shown 
them to be “ coarse, dissimilar in their texture, full of flaws, 
and of a dull lustre, even when smoothed to the best advan- 
tage.” To the flaws of the Assynt- marble I have already re- 
ferred as probably of a surface character; with regard to its 
chemical composition, I may venture to remark, that a marble 
may surely be less pure by three per cent. than that of Car- 
rara, and yet be a real marble notwithstanding; and with 
respect to the polish of which the Sutherland marble is suscep- 
tible, it may be enough to state, that though pieces which I 
attempted polishing for myself are, as may be seen from speci- 
mens on the Society’s table, dull in their lustre, those beside 
them, which I submitted to a marble cutter, bear quite as high 
a gloss as most of the finely variegated marbles of the Conti- 
nent. 
Above this great limestone bed there occurs a second more 
than equally great deposit of quartz rock, generally of a white 
color, but in some of its strata tinged with red. It is truly a 
vast formation; forming, though laid along the surface at a 
low angle, by much the greater part of some of the loftiest 
