24 Dr Boue*s Observations on the 



we do not see any reason for considering the London clay as an 

 equivalent of the whole mass of the Paris tertiary limestone ; 

 and, as we reject the plastic clay as a distinct formation, arran- 

 ging it as subordinate to the limestone, we do not see the neces- 

 sity of a plastic clay in England. No one in England would 

 have thought of separating the plastic clay and the London 

 clay, if that formation had not been proposed and established at 

 Paris ; now, however, as that opinion is admitted to be errone- 

 ous, it is plain that there is no longer any necessity for search- 

 ing for it in England. In short, the London basin seems to us 

 to be only a portion of that vast basin of Northern Europe, 

 where the superior deposites predominate, and not at all an equi- 

 valent of the Parisian one. 



At page 109, on the locality of Haring in the Tyrol, our au- 

 thors reproach me with having overlooked the marine shells ; if, 

 however, they turn to my work on Germany (Geognostiches 

 Gemalde Deutchlands mit rucksicht auf den benachbarten, 

 Laiidern 1829), they will find, at page 403, that we discuss 

 what genera of marine fossils are to be found there. Haring 

 appears to have been a kind of lagune in a longitudinal valley, 

 which, communicated by some rents with the Bavarian tertiary 

 sea, but the rest of the valley of the Inn was formed by far later 

 fissures, for it does not contain tertiary rocks. On the other 

 hand, it is well known that Haring presents some dubious cha- 

 racters which have induced some observers to place it in the green 

 sand, although still the most plausible arrangement is with the 

 tertiary lignites. 



In regard to the Nagelfluh (p. 109), they confess not to 

 be completely acquainted with it ; but they lay much stress 

 upon the opinion that it is a tertiary deposite. It cannot be 

 doubted that there are nagelfluh or calcareous conglomerates in 

 the true molasse. Other similar beds occur also in the upper- 

 most tertiary formation, as at Vienna ; and even the alluvial 

 soil contains great deposites of nagelfluh, as at Salzburg, and in 

 the Austrian alpine valleys. But there is also another conglo- 

 merate, a very thick deposite, which borders some parts of the 

 Alps, especially in Switzerland, which, according to every well* 

 informed geologist, has very peculiar characters, viz. that it con, 

 tains not only debris of all the different secondary alpine limestones 



