GSS 



maintained by continual growth from the posterior extremity of each 

 tooth. Details were given of the genera Passalodonund Ameihodon ; 

 and it was stated that Edaphodon and Passalodon offer combinations 

 of the characters of cartilaginous and bony fishes. In the stratum 

 in which these remains were found, Mr. Sibthorpe has also dis- 

 covered portions of the carapace of an Emys, resembling that of the 

 London clay; and Sir Philip Egerton possesses a fragment of a tooth 

 found at Sheppy resembling the teeth of the Edaphodon of Gold- 

 worth Hill. From the agreement, therefore, in the fossils of that lo- 

 cality with those of the London clay, Mr. Lyell's opinion, that the 

 Bagshot sand was deposited during the eocene period, has received 

 additional support. 



A notice, by Dr. Buckland, was afterwards read " On the disco- 

 very of a fossil wing of a Neuropterous Insect in the Stonesfield 

 slate." 



The elytra of several species of coleopterous insects have been, for 

 some time, known to occur in the Stonesfield slate, but Dr. Buck- 

 land believes that this is the first discovery of any remains of Neuro- 

 jitera. The wings of Libellulce are not unfrequent at Solenhofen ; 

 and a neuropterous wing, resembhng that of a Corydalis, has been 

 discovered by Mr. Mantell in an ironstone nodule from Coalbrook 

 Dale. To the notice was appended a description of the wing by 

 Mr. Westwood, from wliich the following is an extract : — " I have 

 compared the fossil insect wdng with the various genera of neuro- 

 pterous insects, both indigenous and exotic, but it agrees with none 

 of them. I apprehend there can be no doubt that it belonged to a 

 tetrapterous insect, and to the order Neuroptera." 



Dr. Buckland proposes to call the fossil insect Hemerohio'ides gi- 

 ganteus, from its being more nearly allied to the recent genus He'me- 

 robius than to any other at present known. 



The last paper read was on some species of Orthocerata ; by Chai'les 

 Stokes Esq., F.G.S. 



In Dr. Bigsby's paper on the geography and geology of Lake 

 Huron* some Orthocerata of peculiar forms are described ; but since 

 the publication of that memoir, Mr. Stokes has received many 

 other specimens, collected during the expeditions of Sir Edward 

 Parry, Sir John Franklin, the late Capt. Lyon, and Capt. Back, and 

 by Capt. Bayfield during his survey of the lakes and the river St. 

 Lawrence. The object of the present communication is to describe 

 some species indicating generic separations among the Orthocerata, 

 and to call attention to certain considerations respecting the relations 

 of the shells to the animals to which they belonged. 



The first generic distinction adopted by Mr. Stokes consists in a 

 large siphuncule, much dilated in each chamber, and contracted at 

 the parts where the septa are attached to it. Within the siphun- 



* Geological Transactions, 2nd Series, vol. i. p. 195 et seq. Pis. 25 and 26. 



