402 PEOCBEDINGS OF THE GEOLOGICAL SOCIETY. [May 10, 



fibres do not show the longitudinal lines always present in Proto- 

 spongia major, nor are they flattened ; but in this specimen the fibres 

 are much larger than in the one figured by Mr. Salter in Quart. 

 Journ. Geol. Soc. vol. xx. pi. xiii. 



EXPLANATION OF PLATES XV. AND XVI. 



(^Illustrative of Fossils from the Longmynd EocJcs of St. David's.) 

 Plate XV. 



Fig. 1. Head oi Plutonia SedgwicJcii, Hicks. 

 1 a. Portion of the same, magnified. 



2. Head (small) of Plutonia SedgwicJcii. 



3. Free cheek of P. SedgwicJcii. 



4. The same, large size. 



6. Margin of the head of a large specimen of P. SedgwicJcii. 

 6, 7, 8. Pleura and part of the axis of P. SedgwicJcii. 

 9. Paradoxides HarJcnessi, Hicks, head of. 

 10. , labrum, 



11. ■ , a thoracic segment. 



12. Discina pileolus ? Hicks, from the red rocks at the base of the purple 



sandstones. 



12 a. ■ , magnified. 



13 and 14. Lingulella primmva, Hicks. 

 15, 16, 17. Leperditia ? caTnbrensis, Hicks. 

 15 a, l6 a, 17 a. , magnified. 



18. Part of the head of a Trilobite from a bed at the base of the purple rocks, 

 about 3000 feet below the " Menevian group." 



Plate XVI. 



Fig. 1-4. Conocoryfhe Lyellii, Hicks. 

 5-7. , narrower form. 



8, solvensis, Hicks, head of. 



9. Microdiscus sculptus. Hicks. 

 9 a. , magnified. 



10. , tail of. 



10 a. tail of, magnified. 



11. Agnostus ca'mhrensis,'S.\c\a,he!?)jdi of. 



11 a. , head of, magnified. 



12. , tail of. 



12 a. , tail of, magnified. 



13. TJieca anfiqua, Hicks. 



14-17. Protospongia ? major, Hicks, from the Longmynd Eocks, St. Dayid's. 



18. , from the " Menevian Group," St. David's. 



19. Protospongia? flabella, Hicks, from the "Menevian Group," St. David's. 

 19 a. , portion magnified. St. David's. 



20. fenestrata, Salter, from the "Menevian Group," St. David's. 



Discussion. 



Mr. Hughes bore testimony to the admirable work done by Mr. 

 Hicks, who had, almost unaided, worked out the geology of that 

 district. Allowing that many subdivisions and new specific names 

 had with great advantage been introduced into petrology, he de- 



