94 Lieut. Baddeley on the geognosy 
exceedingly imperfect, being tinged with grey, brown and 
yellow, and mottled with transparent parts, which give it 
the appearance of having been stained with oil. But its 
most formidable defect is its Jaminated structure, and the quan- 
tity of mica with which it is contaminated ; to this we are 
to attribute the corrosion and almost entire ruin of so many of 
the specimens, the action of the weather desolving those parts 
of the stone where the mica is most abundant, and cutting deep 
fissures through many parts of the work. It is peculiarly un- 
fortunate, that the two most admirable specimens which are 
calculated to excite in the minds of artists 2 mixed feeling of 
wonder and despair, the horse’s head, and the ‘Theseus, 
should be those which have suffered most. Had they been 
fortunately executed in the more uniform and durable stone of 
Carrara, these works might still have been preserved to us in all 
there original perfection of drawing and surface. Even the ham- 
mer of the Turk would have rebounded with little injury from 
the marbles of this texture, while the micaceons stone of Pen- 
telicus, splitting in the direction of its laminz, has permitted 
the complete mutilation of many valuable sculptures. 
«¢ We have no geological information with regard to the 
relation of these stones, The great resemblance of the Pentelic 
tothat of Glen,Tilt, in aspect and composition, renders it 
probable, that like this, it lies in mica slate, forming beds par- 
allel to, and interstratified with, that rock : that the others have 
similar relations to the primary rocks, we should have con- 
cluded on general geological principles, had we not already 
seen that the white marble of Sky, which has given rise to this 
discussion, belongs to the secondary strata. 
«© We have now to examine the white marbles which have 
been discovered in our own islands, for the purpose of compar- 
ing their relative properties, and the value which they are likely 
to possess in sculpture, I am unfortunately unable to give any 
agn 
