4t06 Mr. Murchison on the Tertiary and Secoiidary Rocks 



washed out, the fossilist is enabled, when the river is low, to 

 collect the remains of each layer by inclosing himself between 

 the projecting beds of stone, the upper and lower surfaces of 

 which are thus placed on either side of him. The perfect 

 state of preservation of the shells in these vertical beds is a 

 distinct proof that the dislocation of sti'ata, even when vertical, 

 does not, as some geologists have imagined, necessarily pro- 

 duce any derangement or destruction of their organic con- 

 tents. These strata mount into a steep hill, on the summit of 

 which is the little church of St. Bovo, at least from six to seven 

 hundred feet above the river, and where they form an outline 

 nearly as peaked and grotesque as that of the adjoining dolo- 

 mite, or of any other crystalline rocks; thus showing that ex- 

 ternal form may be entirely due to the inclination of the beds, 

 without any reference to the structure or age of the rock. 

 After passing along the edges of a considerable thickness of 

 blue marly strata, much of which has been swept away by the 

 river, there occurs a very compact brown and pink-coloured 

 limestone, containing small multilocular shells and nummu- 

 lites. This limestone is the lowest of the members of the ter- 

 tiary series, and the beds having now become absolutely ver- 

 tical, are seen in contact with the red scaglia with flints or re- 

 presentative of the chalk, without the slightest appearance of 

 unconformable deposition, the edges of the two formations hav- 

 ing a parallel direction from W. to E., as seen in the vertical 

 piers on both sides of the river, on the west bank of which 

 they rise together into a lofty hill. (See Section, fig. 2.) 



The upper beds of the scaglia are red and fissile, precisely 

 like those described at Possagno, with flints both in layers 

 and in nodules, and few or no organic remains. The lower 

 beds are thicker and more compact, and gradually losing the 

 red colour, they pass into a beautiful white saccharoid mar- 

 ble, a variety of which is largely quarried (and called Bi- 

 ancon di Pove) *. The vertical edges of this rock are seen 

 for several hundred feet along the right bank of the Brenta ; 

 when near Campese it seems to pass into a dolomitic lime- 

 stone, the beds of which are also vertical and conformable 



to 



* Maraschini in his " Saggio Geologico del Viccntino" is inclined to consider 

 the scaglia a tertiary formation, chiefly because in the districts he examined, 

 it is unconformable to the inferior or Jura limestone. This author's sec- 

 tions, however, were all made in the country west of the Brenta, where the 

 deposits being traversed by a variety of trap rocks, cannot be selected as 

 proofs that the unconformability of the strata is due to any other than a 

 partial cause; for in the district 1 now describe, and where igneous rocks 

 have not penetrated, it has been shown that all the deposits are perfectly 

 cnnfurmahle. But in some ot the adjoining regions to the west, and even 

 when intermixed with volcanic rocks the same deposits arc again strictly 



conformable; 



