R. ETHERIDGE, JUN., ON LOWER-CARBONIFEROUS INVERTEBRATE. 21 



Genus Orthoceras, Breynius. 



Orthoceras, sp. ind. PL II. figs. 33, 34. 



Obs. Mr. Henderson possesses several fragments of this genus, 

 from the Woodhall and Granton shale, which I think may all be 

 referred to one species. The shell tapers gradually, the section is 

 circular, and the siphon small and central. There is a very finely 

 striated epidermal covering, the striae being very fine, close, and slightly 

 waved ; but they must not be confounded with the sharp annular 

 strise of 0. cinctum, Sow. These characters correspond tolerably 

 well with the description of Orthocera cylindracea, Elem.*; but really 

 so little has been done towards the determination of this and other 

 equally ill-defined Carboniferous Orthoceratites that the reference of 

 mere fragments to any of them is, to say the least of it, unsatisfac- 

 tory. A revision of the Carboniferous Orthoceratites will, whilst 

 bringing to light some undoubtedly new forms, no doubt tend to 

 abolish quite half the so-called species which have been made, in 

 favour of a few and broad but thoroughly recognizable types. 



Loc. and Horizon. Woodhall, as before ; Granton, in bed of shale 

 behind western breakwater. 



A description of the Invertebrates of the Cement-stone group 

 generally, as developed in the Edinburgh district, and contained in 

 the Collection of the Geological Survey of Scotland, would consider- 

 ably add to the number of the species described in the foregoing 

 sketch. Unfortunately circumstances over which I have no control 

 prevent me from offering a description of these ; and in this instance 

 it is owing to the kindness of Messrs. Henderson and Gall that I 

 am able to so far advance the subject. 



The following Table (p. 22) has been constructed to show the relative 

 occurrence of the species at the localities cited. It will be observed 

 that no less than 18 species occur in the Woodhall shale, whilst at 

 the Craiglockhart Quarry there are six, two of which have not been 

 observed at Woodhall. At Drumsheugh two of the most character- 

 istic shells of the Woodhall shale occur, viz. Schizodus Salteri, mihi, 

 and Pandora tyjoica, mihi, accompanied by Anthracoptera? obesa, 

 mihi. The latter is very characteristic of certain beds at Craig- 

 leith Quarry and Corstorphine Hill, and at the former locality is 

 associated with P. typica, in a similar way as at Drumsheugh. 



III. Remarks on the First Appearance of certain Species in the Cal- 

 ciferous /Sandstone Series of the Edinburgh district. 



We are in possession of little or no published information con- 

 cerning the Invertebrate life of the lower division of the Calciferous 

 Sandstone Series, the Red Sandstone group. Entomostraca are 

 found at one or two localities (such as Estheria Peachii, Jones, in 



* Thomson's Annals of Philosophy, 1875, v. p. 202. 



