10 . II. RELICS. Phenomena, 



g. A petrifaction often consists of several distinct 

 minerals, f 



h. Sometimes only of one. 



i. The common constituent substances of petrifac- 

 tions are earths and stones of the calcareous, argil- 

 laceous, or siliceous class (vide . III. Substance.) 



k. Some of the other earths, and also the metal- 

 lic,, saline., and inflamable bodies, occur in petrifac- 

 tions, but much less frequently, than the substances 

 above mentioned. 



/. Animal petrifactions are observed to be less 

 common, in proportion to the greater degree of lo- 

 comotive power the originals possessed, ff 



m. The vegetable petrifactions most common, are 

 such, as bear the" form of plants growing in moist 

 and boggy grounds, f f f 



ii. The petrifactions hitherto recognized, how- 

 ever, as bearing the forms of plants or animals, known 

 to exist at present, are very few, compared with those, 

 the living species of which have not, as yet, been dis- 

 covered. 



t Thus chalk and flint often form separate parts of an echi- 

 nite ; and in Derbyshire, chert, calcareous spar, bitumen, and quartz, 

 are frequently incorporated together in the same shell. 



ft Shells and zoophytes abound in petrifactions; fish and apte- 

 rous insects are more rare The petrified remains of the mammalia 

 are still less frequent ; and winged insects and birds have, perhaps, 

 never been found in this state. 



ttt Particularly some species of the cryptogamia and gramina. 



ttft It it true, some of our European petrifactions have been 



