Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 75 



Biidesheim-shales, and Iberg coral- and braehiopod-limcstone. In 

 the Middle Devonian he recognizes Stringocephalus-Yimestone, Cal- 

 cedla -limestone, Calceo fo-shales, and possibly also Goslar-beds. In the 

 Lower Devonian he finds the Upper and Lower Coblenz stages, and 

 ' Siegen Grauwacke,' especially represented by a small but typical 

 fauna at Looe. This general agreement is further increased by the 

 appearance of numerous ' greenstones,' which, just as in Nassau and 

 the Harz, are accompanied by schalsteins." 



Mr. Ussher's paper relates more particularly to the area north of 

 the Dart and east of Dartmoor, and it is satisfactory to find that 

 his views are fairly in agreement with those of Herr Kayser, the 

 value of whose identifications he readily acknowledges. Although 

 the lithological constituents of the Upper, Middle, and Lower 

 Devonian beds are broadly distinguishable, yet there is no definite 

 lithological boundary between the groups. The Lower Devonian is 

 mainly indicated by the occurrence of sandstone and grit ; but the 

 upper beds are slates or shales passing without distinction upward 

 into the Middle Devonian slates. In no part of the Lower Devo- 

 nian of this district have igneous rocks been found. The Lower 

 Devonian of the Torquay and Paignton areas is described with 

 especial attention to the fossils, and the Author embraces the oppor- 

 tunity of correcting a mistake into which he, and latterly also 

 Mr. Champernowne, fell with regard to the position of the Cocking- 

 ton Grits, which may, he says, be placed in the Lower Devonian on 

 palaeontological evidence quite as strong as any furnished by the 

 Torquay promontory. He considers that at present the evidence is 

 not sufficient to justify the subdivision of these beds into Upper 

 and Lower Coblenzian. 



The Middle Devonian is, of course, the most interesting series ; 

 and here I would remark that, in the Abstract of this paper, the 

 sequence differs from that given in the Quarterly Journal. Assuming 

 the latter to represent Mr. Ussher's final views, he makes the Ash- 

 prington volcanic series underlie the Middle Devonian Limestones 

 (vol. xlvi. p. 493), thereby apparently endorsing the opinion ex- 

 pressed by Mr. Worth that, in the Plymouth district, the volcanic 

 rocks were mainly below the limestone. Further on, however, he 

 remarks that the Ashprington series may represent continuous or 

 intermittent activity up to the middle of the Frasnian. In ascend- 

 ing sequence, then, the following is now held to be the development 

 of Middle Devonian rocks in this area. At the base are the Eifeliau 

 slates, characteristically developed in Berry Park, bounded on the 



