YoL 57.] PHYSICAL DEVELOPMENT OP ANTTGFA. 497 



species (of three genera) and some additional varieties as here 

 named ' : — 



Astraa crassolamellata, sp. nov,, with varieties magnetica, pulchello, nobilis, 

 minor, Nugentl, and magnijica ; A. antiguensis, sp. nov. ; A. cndoth,cccda, 

 sp. nov.; A. tenuis, sp. nov.; A, harhadensis, sp. nov.; A. radlata, 

 Lamarck, var. intermedia ; A. costata, sp. nov. ; Eliodarcsa irregularis, 

 sp. nov. ; Alvcopora D(sdal(Ba, Blainv., var. regularis ; A. microscopica, 

 sp. nov. ; A. fenestrata, Dana. 



I tiave seen no determination of the shells collected by Xugent, 

 but with regard to some of them, Duncan says that they were 

 unfortunately determined by some good authorities to be specifically 

 identical with forms now existing in the reefs round the island. 

 I might suggest that these recent types of shells may have come 

 from the lower altitudes above the sea, and belonged to a different 

 horizon not distinguished by the collector from the AYhite Lime- 

 stone Series, for, as already stated, the earlier observers confounded 

 an overlying accumulation with the great formation now being 

 studied. 



My collection of corals has been kindly determined for me by 

 Dr. T, Wayland Yaughan, who found the following species : — 



OrhiccUa endothecata, Duncan 



Trochosmilia sp. nov. 



Stylophora sp. 



Stephanocmiia sp. 



Astrocoenia ornata, Ed, & H. 



Brachyphyllia sp. 



Orbicella {Astrcea) crassolamellata, 



Duncan. 

 Orbicella cellulosa, Duncan. 



(=cavernosa, Linn.). 

 Orbicella sp. 

 Syniphgllia sp. nov. 

 Astroria polygonalis, Duncan. 

 Oroseris sp. nov. 

 Alveopora regularis, Duncan. 

 Porites sp. nov. (?). 



Besides these corals a species of Orhitoides was also found. 



This list includes eight new or undetermined species of other 

 genera, not found by Duncan, and six species common to the 

 two collections. Two of these species are those which Duncan 

 found in collections from the marl-beds ; three from those belonging 

 to the chert-beds (that is, midway within the great beds of tuff) 

 or in the tuff itself; and one species common to the marl and 

 the lower beds. Thus while Duncan recognized a difference in 

 the fauna of the lower and upper beds, he found that they were 

 closely allied, and the present collection still further emphasizes 

 this point. Accordingly it would appear that the underlying beds 

 of tuff with the overlying White Limestone form scarcely more 

 than one geological unit, although characterized by great changes 

 in the physical conditions during the accumulation of the system. 



This collection of mine contained old types only. Duncan iden- 

 tified some of the species as belonging to the Miocene Period 

 of the Old World. A few he found to be recent, but related to 

 those of other West Indian islands, though the nearest analogies 

 are found in the Indian and Pacific Oceans. The majority of 

 the species are peculiar to Antigua, but none of them have any 

 relationship with tiie living forms in the adjacent waters, showing 

 a complete gap between them and the coral-fauna of the marls. 



^ Quart. Journ. Geol. Soc. vol. xix (1863) p. 410. 



