1 60 On some zoological Facts 



On the summit of those niountauis, already mentioned^ 

 there is found, at the height of more than 15 or 1800 feet 

 above the level of the sea, a great number of shells incrusted 

 in the middle of the madreporic masses which they form. 

 The most of these shells are in the siliceous state : some of 

 them, still in the calcareous state, are more or less altered 

 and friable. There are some monstrous ones among them; 

 I have seen several individuals, and every person belonging 

 to the expedition might have seen them also, which were 

 not less than four or five feet in length. All these large 

 shells evidently belonged to the genera hippope and tridacne 

 of Lamarck ; and, what is more important, the fossil in- 

 dividuals have such a resemblance to those of the same 

 genus found alive on the sea shore at the bottom of the 

 mountains, that I have thought proper to consider them as 

 the same in my General Topography of the Bay of Cou- 

 pang. Even the gigantic proportions of the fossil tridacnes 

 are found in the living ones. I myself saw a valve which 

 served daily as a trough to five or six hogs. In the Dutch 

 fort there is another in which the soldiers of the garrison 

 wash their linen. The absolute want of colour, common 

 to the fossil and living tridacnes, is another reason for 

 their identity. The case was the same with several kinds 

 of zoophites, which, existing still on the coasts, seem to 

 be so identic with some of those forming the mountains of 

 tha,t part of the island, that I made no hesitation in con- 

 sidering them as sucb. Since my return to Europe, how- 

 ever, having had occasion, in examining the beautiful col- 

 lection of M. Defrance, to remark how easy it is to be 

 mistaken in this respect, I must freely confess that I can 

 no longer venture to warrant this identity, however pro- 

 bable it may appear, as my observations were not made 

 with that minute attention which the subject deserves, and 

 as whole specimens are not to be found in our collections. 

 While I regret that I suffered so valuable an observation 

 to escape me, I must mark Timor as the place most proper 

 for determining the delicate and interesting question in 

 re2:ard to analogous living individuals, at least in the last 

 classes of the animal kingdom. 



Before I terminate what relates to petrified shells, it 

 seems to me indispensably necessary to say a word of in- 

 crusted shell?, which are too often confounded with the 

 former. 



B. Of 



