Vol. 6 7. J ASSOCIATED HOCKS OF NORTH-EAST MONTGOMERYSHIRE. 457 



deposits of both Britain and America. The fossils of the grits and 

 the shallower-water types in general are more distinctively British. 

 This, of course, is a phenomenon which might have been expected. 

 The fossils described will be offered to the Museum of Practical 

 Geology, Jermyn Street ; while the remainder of the collection will 

 remain in the Geological Laboratories of the Imperial College of 

 Science & Technology. 



w oj 



Concluding Remarks. 



In conclusion I desire to express my gratitude to Prof. Watts, at 

 whose suggestion I entered upon this work, and from whom I have 

 received much encouragement and advice. My sincere thanks are 

 also due to Prof. Lapworth, who kindly placed at my disposal much 

 of the material collected by the late Mr. Bickerton Morgan. 



EXPLANATION OF PLATES XXXIII-XXXVI. 

 Plate XXXIII. 



Geological map of part of North-Eastern Montgomeryshire, on the scale 

 of an inch and a half to the mile, or 1 : 42,240. 



Plate XXXIV. 



Quarry-section in the Buttington Shales, Buttington Brickworks, showing 

 the high inclination of the strata against the ' diabase ' intrusion at Cefn 

 and the effect of soil-creep at the surface. (See p. 436.) 



Plate XXXV. 



Fig. 1. Grit-band in the calcareous beds of the Upper Gaerfawr Grits, 

 showing fragments of felspar and of fine-grained basic igneous rock. 

 Magnified 50 diameters. (See p. 428.) 

 2. The Welshpool Dyke, showing columnar structure in concentric layers. 

 (See p. 447.) 



Plate XXXVI. 



Figs. 1 & 2. Trinucleus intermedins, sp. nov. Natural size. (Seep. 449.) 

 Fig. 3. Dionide sp. Magnified 2 diameters. (See p. 450.) 



4. Primitielia unicornis Ulrich, var. 1. Left valve. Magni- 



fied about 16 diameters. (See p. 452.) 



5. Pr. unicornis, var. 2. Right valve. Magnified about 



1() diameters. (See p. 452.) 



6. Ctenobolina of. ciliata Emmons. Right valve. Magnified 



about 10 diameters. (See p. 452.) 

 Figs. 7, 8, & 9. Cyclonema donaldi, sp. nov. Natural size. (See p. 453.) 

 Figs. 10, 11, & 12. Bellerophon (Protowarthia) portloc/ci, sp. nov. Natural size. 

 (See p. 453.) 

 13 & 14. Carinaropsis acuta. Ulrich & Scofield. Adult. Natural size. 



(See p. 454.) 

 Fig. 15. C. acuta. Young specimen. Natural size. (See p. 454.) 



16. Eccyl iomphal us cant ign 'us Ulr., var . cambrensis, nov. Natural 

 size. (See p. 454.) 



17. Cyrtolites parvus Ulr., var. carinatus, nov. Natural size. 

 (See p. 455.) 



Figs. 18 & 19. Lingula obtusiformis, sp. nov. Natural size. (See p. 455.) 

 20 & 21. Streptelasma (!) aff. breve Ulr. Natural size. (See p. 455.) 



Q.J.G.S. Xo.267. 2 1 



