492 FOSSIL INVERTEBRATED ANIMALS. 



It is even extremely probable that the depositions in which 

 they are found abundantly, and in good preservation, have 

 been so circumstanced, that these animals were surprised and 

 enveloped there at once, as it were by the effect of a volcano, 

 or some other sudden cause. It is remarked, indeed, that the 

 greater part of the places in which they are found have been 

 volcanized, as, for example, the Philippine Islands, the coast 

 of Coromandel, and various other situations. 



These fossils have been found in many different strata. 

 Those which were most anciently buried are anterior to the 

 formation of the crystaUized rocks, which, for a long time, were 

 confounded with the granite, and which differ from them only 

 in not containing quartz. Some have been found in calcareous 

 strata anterior to the chalk. The former are the asaphi, the 

 paradoxites, and probably the ogygise ; the latter are the caly- 

 menes, the cancer Leachi, the atelecyclus rugosus, &c. Others 

 belong to the formation of the chalk itself — such are the pa- 

 guri of Maestricht— and others to the formation of the ceri* 

 thian limestone. A great quantity has been found in the 

 deposition of foliated limestone in the margraviate of Anspach, 

 whose geological position does not appear to be well deter- 

 mined. They are principally the limula Walchii, the eryon 

 of Cuvier, &c. Some are found fossil, and yet anomalous, in 

 the limestone formation of the environs of Verona. A great 

 number are also found in the pottery earth in the East Indies, 

 respecting which there is no positive information. A lobster 

 and a crab, both unknown in the living state, are found com- 

 monly in the lias at Lyme. 



With respect to their state of preservation, we may finally 

 remark, that most of them have but their claws and antennae. 

 Some are totally changed into calcareous stone 3 of others, the 

 internal mould alone is visible, or the external impressions are 

 very clear. There are some whose testa has assumed a deep 

 brown or black tint, and others are covered with a slight pel- 

 licle of sulphur of iron, &c. 



