80 



forming the deposit attains its greatest thickness in the bluff 

 nearest to the township, and as the same relative characters 

 are maintained at other places where the beds are exposed I 

 have chosen this point as the most suitable for illustrative 

 purposes. [The accompanying diagram will show the relative 

 extent and position of the various beds.] 



Conceive, therefore, a white, beetling sea-cliff, whose base is 

 obscured by enormous blocks of sandstone which, by the cease- 

 less undermining action of the sea, have recently been dis- 

 lodged from the various ledges high overhead. 



Those restless sea waves by which they were originally 

 formed are now at once engaged in their destruction, and in 

 re-arranging out of the same materials a very similar set of 

 sandstone beds in the quiet coves of the neighbourhood. 

 Thus we have the work of destruction and construction car- 

 ried on by the same agency, and although we may find in the 

 new arrangement a certain parallelism with the older forma- 

 tion ; yet there are differences at once striking and instruc- 

 tive. For example— while the particles of sand forming the 

 original rock have only been subjected to a little more tear 

 and wear, the included organisms are in every case wholly dis- 

 solved. It is true that the existing types of life which find a 

 home and a grave in the new formation may have secreted in 

 their tests the same elements which formerly entered into the 

 composition of the tests of the organisms of the older forma- 

 tion, but the forms themselves are very different in appear- 

 ance. Wei'e the present sands consolidated and elevated into 

 a series of cliffs corresponding to those which now exist along 

 the shore, the most careful observation might fail to find any 

 organism having its exact counterpart in the older formation. 

 The characteristic shells — ■ 



Triqonia semi-undiilata ; Pectuncuhis laticostafns ; Cucullea 

 corioensls ; 0. caiiiozoira ; Voluta anticinqulata ; V. welcli, etc., 

 and the Polyzoa CeUepora gamhierensis ; C. nummularia ; C. 

 hemispherica ; G. spoiu/iosa ; Sdlicornaria sinuosa. — Corals — 

 Plachotrochns deltoiileus; F. elongatvs, etc., etc., of the older for- 

 mation, are not found in the new formation, whilst the 

 characteristic shells of the latter — Trigonia margaratacea ; 

 Waldheimia australis ; Venus roborata ; Fhasianella australis ; 

 Nassa pauperata, Risella nana, etc., etc., are nowhere to be 

 found in the beds of the former. 



I shall now give a brief description of the various rock di- 

 visions of the section given in the diagram, and in following a 

 downward order I shall offer such observations as may be 

 necessary to impart to the members of this Society; some 

 knowledge of the composit and relative extent of the various 

 beds and their included organisms. My work in this particular 



