202 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



The Modiolae which perforate rocks live at various depths below 

 the surface of the sea, and although there are instances of marine 

 animals inhabiting a mixture of sea- and fresh-water, yet they are 

 comparatively rare. In the present instance we find three genera, 

 which are very numerous — the Modiolse, the Arcse, which seem to 

 have sheltered themselves in the untenanted abodes of the former 

 genus, and the Serpulee, which attached themselves to the inside of 

 the shells of the Modiolae, or to the sides of the cavities made by them. 



77. The facts which have been adduced (par. 48 et seq.) to prove 

 a subsidence of the adjacent land are conclusive on that point, and 

 concur with the section immediately behind the temple, to show 

 that at one period its pavement must have been considerably below 

 the Mediterranean. But that section cannot be adduced as an argu- 

 ment, until we have refuted a theory which has been offered to ex- 

 plain the history of this temple. 



It has been supposed that a great storm which partially destroyed 

 the temple threw up a bar between it and the sea, and filled the 

 area with sea-water containing the young of the several shell-fish 

 which are found in the columns. 



The objections to this theory are — that it supposes a salt lagoon 

 to have existed for many years in a hot climate, with its surface 9 

 feet above the level of the adjacent sea, and without any supply of 

 water; when evaporation must soon have dried it up, and the water 

 from the hot spring could not have supplied it without leaving traces 

 of another incrustation similar to those described as the dark deposit 

 and the great incrustation ; that the supposed lagoon must have 

 existed in a cavity in a porous sandy soil, as is proved by the section 

 close to the temple (par. 41) — and yet that a pressure of 9 feet of 

 water did not cause such a reservoir to leak. 



If it be urged that a lake has alieady been supposed to have ex- 

 isted in a former state of the temple, and that these objections are 

 equally fatal to that lake, the answer is, that in the former instance 

 there was a constant supply of water from the hot spring to replace 

 the loss by evaporation and leakage — that the depth of this lake was 

 much less — and that the deposit of carbonate of lime from the hot 

 spring might have contributed to render its sandy bottom less per- 

 vious to water. 



Either of these objections is fatal to the lagoon theory. When it 

 is added, that this hypothesis is insufficient to explain the first in- 

 crustations without new suppositions — that it does not remove the 

 necessity for a subsidence ol" the ground, which it was invented to 

 supersede — that there ate clear and unequivocal proofs of such 

 changes of level in the immediate neighbourhood of the temple, and 

 that the section close to it concurs in pjoving that the ground on 

 which it stands was subject to those changes — it is quite unphiloso- 

 phical to admit an hypothesis supported by no fact, and refuted by 

 many. 



It seems then that the temple subsided into the sea ; but whether 

 this happened slowly or at intervals, by repeated shocks of earth- 

 quakes, does not appear. Nearly at its lowest point there are indi- 



