period ; and the physical conditions of such an area were never present during the deposition of the Madreporaria, Polyzoa, Echinodermata, and Mollusca, which have a facies characteristic of all the European marine tertiary deposits above the Nummulitic. They were subjected to frequent volcanic outbursts, which covered large areas with basalt and ash, and they were covered, after the general upheaval of the centre of Australia, with lacustrine, dune-, river-, and torrent-deposits, whose depth testifies to the enormous denudation of the older rocks. The condition of the high land on the extreme east and west of Australia was probably that of dry land during the whole Cainozoic period ; and these districts bounded the tertiary sea.
EXPLANATION OF PLATES XIX-XXI.
Plate XIX.
Fig. 1 a, Caryophyllia viola, Duncan and Woods, X 2 ; lb, calice, magnified ;
1 c, costae.
2 a, Trochocyathus meridionalis, sp. n., X 2 ; 2 b, calice, magnified ; 2 c, costae.
3 a, Trochocyathus Victorioe, sp. n., X 2 ; 3 b, calice, magnified ; 3 c, costae.
4 a, Deltocyathus italicus, Edw. & II., var. australiensis, calice, magnified;
4 b, base, magnified ; 4 c, costae, magnified.
5 a, Sphenotrochus australis, Duncan, X 2 ; 5 b, calice, magnified.
6 a, Sphenotrochus excisus, Duncan, X 2 ; 6 b, calice, magnified ; 6 c, portions of calicular margin, magnified, to show relative position of costae and septa.
7 a, Conotrochus M'Coyi, sp. n., X 2 ; 7 b, calice, magnified.
8 a, Conotrochus typus, Segu., var. australiensis, X 2 ; 8 b, calice, magnified ; 8 c, epitheca, magnified.
9, Flabellum gambirense, Duncan, X 2.
10 a, The same, X 2; 10b, calice, magnified; 10 c, epitheca, magnified.
11, Flabellum Victorioe, Duncan, X 2.
Plate XX.
Fig. 1 a, Flabellum Candeanum, Edw. & H., nat. size ; 1 b, calice, magnified;
1 c, base of corallum, magnified ; 1 d, side view of a septum, magnified.
2, Flabellum distinctum, Edw. & H.
3 a, Placotrochus elongatus, Duncan, slightly enlarged ; 3 b, calice, magnified; 3 c, peduncular extremity, magnified.
4 a, Placotrochus deltoideus, Duncan, nat. size ; 4 b, columella and septa, magnified.
5, Conosmilia elegans, Duncan, enlarged.
6, Amphihelia incrustans, sp. n., enlarged.
7 a, Paloeoseris Woodsi, Duncan, enlarged ; 7 b, septa, magnified, showing synapticulae.
8, Cycloseris tenuis, sp. nov.
9a, Conosmilia striata, Duncan, enlarged; 9 b, calice, magnified ; 9 c, epitheca, magnified.
10 a, Conosmilia anomala, Duncan, nat. size ; 10 b, calice, magnified ;
10 c, upper part, magnified, showing columella and endotheca.
11 a, Conosmilia lituolus, sp. n., enlarged ; 11 b, calice, magnified.
12 a, Antillia lens, Duncan, septa, magnified ; 12 b, side view of septum.
Plate XXI.
Fig. 1 a, Balanophyllia campanulata, sp. n. ; 1 b, part of calico, magnified;
1 c, costae, magnified.
