i899 H. WINWOOD— CARRARA QUARRIES 67 



were held, a great advance has taken place in our know- 

 ledge as to the position and formation of crystalline rocks. 

 Crushing, faulting, over-thrusts and shearing have been 

 accepted as explanatory of much that has been hitherto in 

 dispute. That a great crush and strain has taken place no 

 one can doubt. There is evidence, too, of faulting, the 

 extent of which, however, requires more time than we had 

 at our disposal to work out. From the diagrammatic 

 section there is an apparent dip of the various beds at a 

 high angle — in some instances observed they were nearly 

 perpendicular — but it is difficult to ascertain in these 

 crystalline rocks whether this was the true dip or the 

 result of cleavage. M. Jervis, in his " I tesori sotterranei 

 deir Italia " vol. iv., 1889, p. 261, 8vo., Turin, evidently 

 thinks that this shows stratification, which, he writes, is 

 sometimes well marked, sometimes completely obliterated. 

 He considers the marble to be Pre-palaeozoic. In one 

 quarry (Ravaccione), where the crush was especially 

 remarked, the crushed planes measured from a few inches 

 in thickness to even a thin thread. A specimen taken 

 from this spot measures half-inch in thickness, the faces 

 of the thin slabs being stained a brownish hue from down- 

 ward percolation of iron oxide. 



In any case, whether that section shows dip or cleavage 

 planes, it is clear evidence of great disturbance. And 

 notwithstanding the opinion of the Italian geologists that 

 these are planes of stratification following in orderly 

 succession the Cainozoic and Mesozoic beds which are 

 highly inclined on the flanks of this range, yet, comparing 

 the structure of the Alps, where similar earth movements 

 have taken place, and considering the analogy of this 

 marble with the white crystalline Palaeozoic marble of that 

 range, the more recent view supported by Professors 

 Bonney and Boyd Dawkins seems to be the more likely 

 one — that this marble is of the same age as the schists 



