TYLOE QUATEENARY GEAVELS. 57 



our former paper * on the great Paradoxides such pleuras were de- 

 scribed of great length. In the present species they are shorter, but 

 still appear to be distinctly separated by simple grooves from the 

 circular appendix as in P. Davidis. In P. Loveni they are perfectly 

 soldered, and are indicated only by the increased number of lateral 

 grooves and marginal spines of that fossil ; and in Anopolenus also 

 the limb is many-ribbed and the margin spinose. — J. W. S. 



EXPLANATION OF PLATES II. & III, 



(^Illustrative of Fossils from the Menevian Grou]).) 



Plate II. 



Eigs. 1 & 2, 4 & 5. Conocoryphe applcmata, Salter. Natural size. 

 3. perdita, spec. nov. Natural size. 



6. Embryo of Conocori/phe applanata. Magnified. 



7. Conocoryphe humerosa, Salter. Natural size. 



8. biifo, Hicks. Natural size. 



9-12. Paradoxides Aurora, Salter. 



Plate III. 

 Paradoxides HicJcsii, Salter. 



4. On QuATEEifAEY Geavels. By A. Tyloe, P.G.S. 



(EeadMay 6, 1868 1) 

 [Plates IV.-IX.] 

 Iis" continuation of a paper on this subject in the Quart. Journ. Geol. 

 Soc. vol. xxiv. p. 103, I now submit a number of measured sections 

 selected as instances of the deposition of gravels of different character 

 under different circumstances both of height above the sea- level and 

 distance from the sea. 



The illustrations and remarks in this paper relate to the unfos- 

 siliferous gravels of the rivers Taif, Ehondda, and Cynon, in Glamor- 

 ganshire, South "Wales, to those of the Aire, in Yorkshire, and to 

 the fossiliferous gravels and brick-earths of the lower part of the 

 Thames and Lea rivers, in the counties of Kent and Essex. 



One section of the fossiliferous gravel of the river Avon, at Salis- 

 bury, is given for the purpose of comparison with those of the 

 Thames ; and a section across the valley of the xiire, in Yorkshire, 

 is compared with those in the valleys of the TafF and Ehondda. 



A map of part of Glamorganshire, and a longitudinal section of the 

 bed of the river Taff, with the heights along its course measured 

 above the height of spring tides at Cardiff, have been prepared to 

 define the exact locality of the Welsh gravels alluded to. A similar 

 map and sections of the course of the river Aire, in Yorkshire, with 

 heights measured from the Ordnance datum, are given for compari- 

 son with the Welsh illustrations. 



A sketch-map of part of the river Thames, and of the adjoining 



* Quart. Journ. Geol. Soc. vol. xx. p. 235, pi. 13. f. 2. 



t Eor the Discussion on this Couimunication see Quart. Journ. Geol. Sec, 

 Tol. xxiv. p. 456. 



