212 



ft. in. 



1 . Sandy debris from the oolite, about ... 100 



2. Upper lias shale : this is traversed at twelve feet from 



its base by the thin bed of fissile limestone five inches 



in thickness 60 



3. Lias marlstone, about 20 



90 

 The thin seam of limestone included in No. 2 is remarkable for 

 containing many organic remains not found in any other part of the 

 lias, and most of them nevs^, comprising land as well as marine ani- 

 mals and traces of plants. Among them are two undetermined 

 species of fish with numerous fish-scales and coprolites, two species 

 of Crustacea, the one allied to Astacus (Fabr.), the other to Hippo- 

 lyte (Leach). A species of Loligo, a new Belemnite, a new Ammo- 

 nite (which Mr. Buckman has named A. murleyi), A. corrugatus 

 and ovatus, a small univalve in great abundance, and Inoceramus du- 

 bius. The remains of insects comprise one species of Libellula, 

 which, from the reticulations of the fine wings, seems to belong to 

 the genus jEschna, Fabr., and has been named by Mr. Buckmau; 

 ^. brodiei, in honour of Mr. Brodie ; two species of Coleoptera of 

 undetermined genera, and a wing supposed to belong to Tipula. 

 None of these are of the same species with the insects found by Mr. 

 Brodie in the lower lias. 



From the presence of a similar band of stone with that containing 

 the above mentioned fossils at Churchdown and Robin Hood Hill, 

 liassic outliers presenting the same section as that of Dumbleton 

 Hill, Mr. Buckman supposes that this thin seam is of constant oc- 

 currence in the upper lias of the neighbourhood. He concludes that 

 the period, which the state of things which produced it continued, 

 was not of long duration, and that its deposition was of a quiescent 

 kind. 



3. " Outline of Geological Structure of North Wales." By the 

 Rev. A. Sedgwick, F.G.S. 



§ 1. Introduction. 



The author here describes in considerable detail the geographical 

 limits of the country under notice. For the structure of the Isle of 

 Anglesea he refers to a paper by Prof. Henslow, published in the 

 Cambridge Transactions. The carboniferous series of Denbighshire 

 and Flintshire is passed over with a slight notice, and without any 

 detailed sections. His chief details are confined to the counties of 

 Denbigh, Carnarvon, Merioneth, and Montgomery ; and the southern 

 limits of his survey is defined by an irregular line drawn from the 

 Severn, near Welch Pool, to the coast near Aberystwith. The 

 southern boundary is purely arbitrary, marking only the limits of his 

 survey, and not any physical separation of the older rocks, which 

 are continued in great undulations through all the higher parts of 

 North and South Wales. He then describes the several connected 



