Geological Society. 377 



extremity. The form of the cutting edge is not truncate, as in the 

 recent Chimcera, but prolonged to an acute angle, and bent down- 

 wards like the upper mandible of a bird of prey. The symphysis is 

 smooth and slightly hollowed. The thin polished investing lamina 

 of compact dentine is seen adhering to the surface of the tooth. On 

 the interior surface this is marked with broad transverse irregulari- 

 ties similar to, although less distinct than, those seen in the recent 

 Chim<era. A fragment in Mr. Dixon's collection gives evidence of 

 having belonged to an individual of much larger size than that which 

 furnished the specimens here described. Sir Philip Egerton proposes 

 to name this species Ischyodus Gigas. 



2. " On the occurrence of the remains of Insects in the Upper Lias 

 of the county of Gloucester." By James Buckman, F.G.S. 



The remains described in this paper were discovered by Mr. Buck- 

 man in a thin seam of argillaceous limestone in the upper lias beds 

 at Dumbleton, a village twelve miles from Cheltenham, to which his 

 attention had been directed by Mr. Brodie, who had suspected the 

 existence of insect remains in the stratum. The section of Dum- 

 bleton Hill, which is a liassic outlier, presents the following beds. 



ft. in. 



1 . Sandy debris from the oolite, about 10 



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 



90~0 

 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 new, 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 Mschna, Fabr., and has been named by Mr. Buckman 

 A3. 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 has*. 



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. 

 * See Phil. Mag. S. 3. vol. xxiii. p. 529.— Edit. 



