170 Dr. Berger on the Geological features 



of its fossils, and the absolute sameness of its general features, 

 will no longer permit us to describe by a distinct name, this im- 

 portant formation. 



It need not excite any surprize to find the floetz trap Incumbent 

 on a bed of such recent formation, since in the north of Italy it 

 may be seen to rest upon strata still less ancient, and analogous 

 to those wliich occur in the basins of London and of Paris. 



The Irish chalk is seldom of a texture sufficiently loose to soil 

 the hand, and in the few instances where this does take place, it is 

 in a very slight degree : its general colour is either perfect white, 

 or white with a very slight tinge of yellow j towards the lower 

 beds it passes into an uniform ash colour, the texture then becomes 

 still more compact. It is sometimes traversed by slender veins of 

 calcareous spar, these are more frequent in the lower beds : it con- 

 tains (though in very small quantity) kidney shaped nodules of 

 iron pyrites ; but the most striking of its imbedded contents are 

 the flinty nodules which traverse the mass In regular horizontal 

 strata, distant from each other, by an average interval, about two 

 feet and a half; the flints cease in the lowest beds. Among the 

 flints some of remarkable size, and of a regular and apparently 

 organic figure occur j these are known by the name of Paramou- 

 dra, and are also found in the chalk of Norfolk. It is superfluous 

 to describe farther the characters of these beds of flinty nodules 

 than by saying, that they are precisely the same with those pre- 

 sented in every English chalk pit. 



The average thickness of the chalk formation in Ireland may 

 be estimated at between two and three hundred feet ; the upper 

 beds seem to have been partially redissolved before the basaltic 

 mass was deposited upon them, since along the line of junc- 

 tion a confused aggregation of chalk flints exists, imbedded in the 



