278 On the Tertiary and Secondary Rocks forming the 



I. The tertiary conglomerates rise from the plains of Venice, 

 about a mile and a half south of Asolo, at an angle of about 

 20° to 25°, dip S.S.E. ; and to the north of that place they 

 reach to the height of at least seven hundred to eight hundred 

 feet above the level of the Adriatic. The angle of their in- 

 clination increases with their altitude ; and the mountain tor- 

 rents flowing from north to south, expose many of these beds 

 dipping even as high as 40° S.S.E. 



The boulders contained in these rocks are of very great size 

 towards the exterior of the zone, but they become smaller in 

 the lower beds: some of these boulders are of primary rock, 

 but by far the greater number are referrible to the dolomite 

 of the neighbouring Alps ; in the higher beds these are packed 

 together with little or no cementing matter, whilst in the lower 

 they are frequently imbedded in a hard yellow calcareous 

 sandstone forming a compact breccia: still lower there are 

 beds of incoherent yellow sand with some organic remains , 

 and this system may be said to terminate in the escarpments 

 north of Asolo, where a fine conglomerate is seen alternating 

 with beds of blue marl and yellow sand, both containing shells. 

 In the descending series there is no repetition of conglome- 

 rates, and the upper system has therefore a well marked ter- 

 mination*. 



The lower system is ushered in by a chain of conical hills, 

 the highest beds of which consist of a thick-bedded yellow 

 sandstone charged with green grains, alternating with strong 

 beds of calciferous grits, and dipping under the conglomerates 

 at angles varying from 25° to 30° S.S.E. These contain 

 many organic remains ; amongst which are Pectunculi, Pectens, 

 Echini, &c. The surfaces of the beds are further remark- 

 able for the vast quantity of branching stem-shaped bodies 

 resembling Alcyonia. At the base of the escarpment of these 

 hills there is a considerable thickness of blue marl, which is 

 prolonged for about a mile to the north, forming low undu- 

 lations, the beds of which are exposed on the banks of several 

 streamlets running from west to east The characteristic shells 

 of this marl seemed to be Lucina concentrica (Venus concen- 

 trica, Brocchi), Lucina mutabilis (Venus mutabilis, Lamarck), 

 Echini, &c North of the small river at Castel C'ucco, a com- 

 pact limestone rises from beneatli the marls and attains consi- 

 derable elevation. The upper beds have a mamillary surface, 

 but upon fracture are of a solid madreporic structure and 

 bluish colour : below this are strong beds of green slaty cal- 



* In this respect the order of the strata does not coincide with that which 

 Mr. Lyell and myself observed in the valleys of the Bormida, or at the 

 Superga near Turin, where powerful conglomerates reappear very low in 

 the tertiary series, beneath an enormous development ot green slaty mica, 

 ceous sandstone and shale. 



