observable in the Secondary Stratified Rocks. 223 



d. The same kind of beds alternating with light-brown 

 schist, containing a great abundance of ammonites, be- 

 lemnites, and small nodules of iron pyrites. 



e. The same brown schist alternating with a few thin 

 beds of light-coloured compact limestone. 



Jl Light-brown schist alternating with dark-gray thin- 

 bedded limestones as in d. 



2. Brown Shale. — This does not effervesce with acids. 



3. Variegated Beds. — Greenish-blue and reddish argillo-cal- 



careous rocks, more or less schistose, the calcareous mat- 

 ter being often very small. 



4. Brown Sandstone. — Principally siliceous, though some of 



it does contain calcareous matter; is sometimes mica- 

 ceous ; occurs in thick, thin, and schistose beds ; has 

 sometimes been called greywacke; is one of the ma- 

 cignos of the Italians. 



5. Gray Siliceo-calcareous Schist and Sandstone. — For the most 



part contains mica; may be considered as a mixture of 

 calcareous, siliceous, and argillaceous matter, in which 

 sometimes one predominates, sometimes the other ; when 

 the calcareous predominates there is a gray compact lime- 

 stone. The whole is much traversed by veins of calca- 

 reous spar, and even, though rarely, by veins of quartz. 

 Contains a large Jiisns at Vernazza. 

 Such is the section afforded by these mountains, No. 1. being 

 the upper most rock, and No. 5. the lowest. To give, however, a 

 clearer idea of this series, it should be stated, that it is covered, 

 as may be seen near La Spezia, by a micaceous siliceo-cal- 

 careous sandstone, the general colour of which is either brown 

 or gray ; it is mixed with schist, and even argillaceous shale. 

 This is another of the rocks named macigno by the Italians. 

 The mica is sometimes wanting. 



It is not my intention here to enter into a detailed account 

 of the environs of La Spezia, which requires the necessary 

 plans and sections, and is moreover intended for another place ; 

 but it remains for me to show that at least a part of the above 

 section may belong to the oolite formation, and this is done by 

 the ammonites, which are of tliose species found in the lower 

 parts of that series : indeed, as far as our knowledge respecting 

 organic remains extends, the presence of the belenmites alone 

 would seem to show that the limestones, notwithstanding their 

 perfect mineralogical resemblance to what has been termed 

 transition limestones, are of the date of the lias, or some more 

 modern rock ; for as yet we have 7io well authenticated instance 

 of bcltmnitcb having been discovered beneath it. The diange 



in 



