Vol. 67.] FROM THE SOUTH WALES COALFIELD. 173 



expect to find more lowly types in the Lower Series of the South 

 Wales Coalfield at some distant date, or even traces of their presence 

 in rocks of Older Palaeozoic age. Their occurrence may also be 

 regarded as indicating the possibility of a terrestrial fauna some- 

 where in the South Wales Coalfield. 



In conclusion, I wish to acknowledge my indebtedness to the 

 Director of H.M. Geological Survey, who placed the specimens in 

 my hands for study ; to Dr. Aubrey Strahan, F.R.S., for information 

 respecting localities and the stratigraphy of the South Wales Coal- 

 field ; to Mr. J. W. Tutcher for his kindness in photographing the 

 specimens amidst the pressure of much other work; to Mr. B,. E. 

 J. Bush, A.R.C.A., who has prepared the wing-diagrams with great 

 skill and accuracy ; and to Mr. John Pringle, of the Geological 

 Survey. 



EXPLANATION OF PLATES VII-X. 



[The photographs are by Mr. J. W. Tutcher, and the line-drawings by 

 Mr. R. E. J. Bush, A.E.C.A. AH the figures are magnified 2*6 diameters ; 

 the specimens are in the Museum of Practical Geology, Jermyn Street, 

 London, S.W.] 



Plate VII. 



Fig. 1. Figure of Gerablattina arcuata Sellards, to illustrate the terminology 

 of the wing : — 



Redtenbacher. Heer. 



I. Costa. I. Marginal. 



II. Sub-costa. II. Mediastinal. 



III. Radius. III. Scapular. 



IV. Media. IV. Externomedian. 



V. Cubitus. V. Internomedian. 



VI. Anal veins. VI. Anal veins. 



The terminology of Redtenbacher is followed in the text. 



2. Archimylacris sp. indet. and pronotum. [Reg. No. 24508.] (See 



pp. 152, 153.) 



Horizon. — Mynyddislwyn Vein, Gellideg Level, near Maes-y- 

 cwmmer (Monmouthshire). 



3. Hemimylacris convexa, sp. nov. [Reg. No. 24512.] (See p. 156.) 



Horizon. — Shales associated with the Graigola Seam, Clydach 

 Merthyr Colliery, Clydach Valley (Swansea Vale), Glamorganshire. 



Figs. 4 & 5. Archimylacris (Schizoblatta) obovata, sp. nov. [Reg. Nos. 24506 & 

 24507.] (See p. 157.) Left tegmen and impression. A large portion 

 of the inner half of the wing is missing. The impression is more 

 complete. 



Horizon. — Mynyddislwyn Vein, Gwemau Level, near Maes-y- 

 cwmmer (Monmouthshire). 



Fig. 6. Diagram showing the course of the veins in Archimylacris (Schizo- 

 blatta) obovata. 



