638 MR J. W. GREGORY ON THE MALTESE FOSSIL ECHINOIDEA. 



mainly to the influence of similar conditions acting on the allied littoral faunas from 

 which these were derived. In some places it appears rather as if a wave of depression 

 bad travelled northward, and some of the deeper species may then have followed it in 

 its course ; but in other cases the action seems to have been a strictly local change of 

 level. 



If the lower part of the Globigerina Limestone be accepted as Aquitanian, then the 

 Maltese area was the first to sink, the subsidence commencing there at the end of the 

 Tongrian, and though there were periods of slight uplift marked by the coarser lime- 

 stones and the occasional abundance of such species as Schizaster parkinsoni, the per- 

 manent re-elevation did not come till late in the Langhien ; hence it seems that, as part 

 of the Globigerina Limestone is Miocene and part Oligocene, there is in Malta no such 

 sharp line of division between these two systems as can be drawn elsewhere. Further 

 north in Liguria the maximum subsidence was not established till towards the close of 

 the Maltese depression, and it was perhaps still later on the other side of the Apennines. 

 Probably the deposition of the Schlier was not commenced at the same time as the base 

 of the Langhien, while it certainly seems to have lasted longer, and to represent also a 

 part of the Helvetian series ; and similar beds of later age indicate that the same condi- 

 tions still prevailed, though over more limited areas. Above the shore deposits which 

 crept out seaward over the gradually-rising Schlier occur the Badner Tegel and the 

 Pteropod Marls of Tortona, represented on the other side of the Apennine axis by the 

 Corsican Zone 4 dents de poisson. And later still than these Tortonian deposits the 

 " Tegel " of Monte Vaticano and the Zanclean of Sicily continue through the Pliocene 

 the record of the conditions of the deeper basins of the Mediterranean Sea. 



EXPLANATION OF PLATES. 

 Plate I. 



Fig. 1. Cidaris avenionensis, Desmoul., Globigerina Limestone, Malta. B.M., E. 1957. Fig. la, Part of ; 



actinal side; nat. size. Fig. lb, Ambulacral plates enlarged. Fig. lc, Spine on the same slab. 

 Figs. 2, 3, and 4. Cidaris oligocenus, n. sp., Lower Coralline Limestone, Malta. Figs. 2 and 3, Spines. B.M., 



E. 3409. Fig. 4a, Ambulacrum and interradius ; nat. size. Fig. 46, Ambital ambulacral plates 



enlarged. B.M, E. 3401. 

 Fig. 5. Echinus tortonicus, n. sp., Upper Coralline Limestone, Malta. B.M., E. 3402. Fig. 5a, Abactinal 



surface, x 2 dia. Fig. 5b, Side view ; nat. size. Fig." 5c, Apical system. Fig. 5d, An ambital 



interradial plate, magd. 

 Fig. 6. Krliiuus duciei, Wright. Ambital interradial plate. 

 Fig. 7. Echinus tontjrianux, n. sp., Scutella, bed of Lower Coralline Limestone, Malta. B.M., E. 3403. 



Fig. 7a, Abactinal surface, x 2 dia. Fig. lb, Side view; nat. size. Fig. 7c, Apical system. 



Fig. Id, Ambital interradial plate, magd. 

 Figs. 8, 9, and 10. Echinocyamus studeri (E. Sism.), Globigerina Limestone, Malta. Figs. 8 and 9. B.M., 



75,687. Fig. 10a, b, c, x 4 dia. B.M., E. 3427. 

 Fig. 11. Ileteroclypeus Jiemisphaericus, n. sp., Greensand, Malta. B.M., 40,368. Half nat. size. 



