﻿KAISER ON THE GEOLOGY OF THE VICINITY OF TRIESTE. 37 



aluminous matter in these beds, — that they contain exclusively no- 

 thing but remains of Plants, and only contain Nummulites and other 

 animal remains where they alternate with the limestones, as at Ro- 

 jano, — serve to identify these beds, and to prove them to be the 

 lowest member of the macigno in this quarter. Upon it repose in- 

 numerable beds of sandstone and slate-marl, varying in thickness 

 from a line to several feet : here and there iron pyrites and oxide of 

 iron, and delicate dendritic markings are seen ; and over these, heaps 

 of fragments of plants in a highly carbonized condition and not re- 

 cognizable. 



The beds on their under side almost everywhere are marked with 

 protuberances and raised lines, as so frequently occurs on the Vienna 

 sandstone. These sandy concretions even affect the partings of marl, 

 and even sometimes penetrate to the surface of the sandstone beneath. 

 One may almost persuade himself that they are the tracks of marine 

 annelids which they must have excavated in the soft slime, and 

 which have been subsequently filled up with sand. 



The sandstone beds are most developed in the neighbourhood of 

 the limestone, that is to say in their lower division, which is better 

 seen at the tops of the hills than in the valleys ; for which reason 

 the best quarries are those of the Opchinaberg. The same is proved 

 by the borings for two Artesian wells, one of which has been put 

 down in the court of the town hospital, but has not yet been pushed 

 to the depth at which a sufficient supply of water is expected. The 

 Macigno beds near the limestone do not display so many displace- 

 ments, foldings, and bendings as those at a greater distance, which 

 are usually very thin, and so remarkable in their convolutions as to 

 attract the attention of casual passengers. Thus on the coast, be- 

 tween S. Bartolomeo and the Grignano hills, a great anticlinal 

 fold of the whole mass can be observed, causing the beds which on 

 the heights for some toises above the sea dip towards the sea, to be 

 suddenly bent over and dip landward. 



But the most remarkable circumstance about the macigno forma- 

 tion is, that in several spots it contains beds of nummulitic limestone, 

 which are conformably interstratified with the macigno. This ap- 

 pears to be a repetition of what has been* previously mentioned to 

 occur at the junction of the macigno and nummulitic limestone, but 

 which in this instance occurs at a greater distance from the limestone. 

 Thus some way up the Opchinaberg, in a cart-track near the old 

 Opchina road, there may be seen, between beds of macigno, a bed 

 about an inch thick, full of small Nummulites, entirely calcareous, 

 and cemented together by oxide of iron, which soon crumbles to 

 pieces under atmospheric influence. 



On the new Opchina road, about half an hour's walk from Trieste, 

 two pretty thick bands of limestone, not far apart, are seen to be 

 interstratified with macigno. The lower one is broken across and 

 bent completely back upon itself : the upper one is also broken across, 

 but the broken ends are only a little thrust one over the other. 

 These limestone bands in their lower part are loaded with Nummu~ 



* Loc. cit. 



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