316 CARBONIFEROUS LAMELLIBRANCHIATA. 



Observations. — This species was founded by Mr. Kirkby (op. supra cit.) for 

 some very elongate narrow shells, found in the Schizodus Pentlandicns bed at 

 Randerston. I think, from a study of the hinge and from the general characters, 

 that his reference of the shell to the genus Sanguinolites was a mistake, as it 

 possesses far greater affinities with that group of Edmondia of which E. arcuata, 

 Phillips, sp., is typical. I have fortunately been able to obtain a specimen which 

 has the hinge-platej preserved, PI. XXXVIII, fig. 2, which places the advisa- 

 bility of referring the species to Edmondia beyond all doubt. 



Associated with this species at Randerston is E. Pentonensis, from which it is 

 distinguished by its much narrower dorso-ventral diameter and obliquely truncate 

 posterior end. 



Mr. Kirkby thought that E. subplicata was limited to the lower part of the 

 Calciferous Sandstone series of Fife, and gives its distribution as 3000 to 3800 feet 

 below the Carboniferous Limestone. I have, however, obtained the shell from 

 the bed of shale below the limestone at St. Monan's, Fife, which Mr. Kirkby takes 

 as the base of the Carboniferous Limestone of Fife. 



I have examined the type of Portlock's Sanguinolaria plicata, and am of 

 opinion that it does not belong to the genus Edmondia, but has more affinity to the 

 shells hitherto known as Sanguinolites iridinoides, M'Coy. Mr. Kirkby quotes 

 Sanguinolites plicatus from the shales at St. Monan's, and probably he did not 

 recognise that the species found there was the same as his S. subplicatus from 

 Randerston, for in the shales the shell is less crushed, and has the external surface 

 beautifully preserved. The Schizodus Pentlandicus bed, Mr. Kirkby's No. 5 Lime- 

 stone, is most interesting. The upper surface is strewn with shells and shell debris, 

 and evidently represents a beach, for much of the bed is made up of rolled shell 

 fragments and shelly detritus. Large numbers of several genera of small 

 Gasteropoda are strewn over the surface, and some of the best preserved shells 

 have Spirorbis adhering to them. The limestone is a very hard band, 1 foot thick, 

 but the waves wear away the cementing material quicker than the fossil shells, 

 which consequently stand out in relief. The fauna of this bed is, I think, 

 characteristic of littoral conditions. Below and separated from this limestone 

 by a bed of shale 9 inches thick, probably of fresh-water origin, is another lime- 

 stone, 1 foot thick, with plant remains, Naiadites and Ehizodus Hibberti, pointing 

 out the rapid alteration of conditions which obtained during the deposit of the 

 Calciferous Sandstone series of the Fifeshire coast. 



Mr. Kirkby thinks it probable that the shell termed Modiola in the East of 

 Fife sheet, No. 41 of the Geological Survey maps, is the same as Edmondia 

 subplicata. 



