chiefly characterized by bituminous slaty marl, alternating with 

 Posidonia and Monotis limestone ; the middle mass by consisting 

 of slaty clay and alum-shale with a great profusion of our well- 

 known lias fossils ; and the lower part by Gryphite limestone with 

 its underlying shale and sandstone. - 



I have alluded to this detailed section, not only because I know, 

 from personal inspection of the spot, that the author is well 

 acquainted with the position of the numerous fossils which he 

 cites, but also to impress upon you, that differing, as this section 

 does, in lithological featui-es from our British types of Lias, the 

 agreement between the fossils of the two countries is very remark- 

 able, a great number of species being identical with our published 

 forms, whilst othei's are new. It remains, therefore, for good 

 conchologists to ascertain how many of our British unpublished 

 species are similar to the additional German forms ; or otherwise 

 confusion may be introduced by employing two names for the same 

 shells. 



The Rev, P. B. Brodie, to the value of whose minute researches 

 I last year bore testimony, has since discovered insects, of which 

 even the wings are sometimes preserved. He states that they are 

 extensively developed in the bottom beds of the Lias through the Vale 

 of Gloucester, an observation which he has rendered still more im- 

 portant, by showing that these creatures are associated with fresh- 

 water remains and terrestrial plants mixed up with marine shells, or 

 such, at all events, as inhabit estuaries ; thus indicating the tranquil 

 transport of insects and plants from adjacent land, probably at that 

 period, in the form of scattered islands. 



In reference to one member of these deposits, the celebrated bone- 

 bed at the base of the Lias, Mr. Strickland, in observing certain 

 hitherto uninvestigated appearances on its surface, has employed 

 the analogical reasoning of a naturalist accustomed to note the habits 

 of the lower vertebrata. Some of these markings he has sought to 

 explain by the action of fast-swimming fishes ; others by mud-feed- 

 ing fishes probing and turning up the surface, whilst narrow and 

 angular grooves are referred to the movements of an acephalous 

 mollusk, and fine tortuous tracks are supposed to have been caused 

 by the crawling of small annelids. This latter point was previously 

 adverted to by Mr. Atkinson *. 



Wealden. — In enriching the fauna of the Wealden formation by 

 a second discovery of a number of new species of insects in the 

 Vale of Wardour, Mr. Brodie has again proved how much may be 

 done by minute and careful researches, and has shown us how 

 essentially our acquaintance with the former conditions of land and 

 water depend on such information. He observes, that next to the 

 Coleoptera, the most prevalent orders are the Homoptera and Tri- 

 choptera, the first of which now live on plants, similar to those found 

 fossil in the Wealden, and the existing species of the latter hover 

 over the surface of our present streams. From their broken condition 



* Proceedings, vol. iii, p. 126. 



