Fossil Organic Remains. 27 
zechstein with bituminous marl-slate, (muriatiferous gypsum,) 
oolitic sandstone, (argillaceous gypsum,) shell limestone or 
muschelkalk, and white sandstone (quadersandstein), have been 
recognised as distinct, without having any recourse to geological 
characters ; but it does not follow from thence, that the most mi- 
nute investigation of these characters, or, to speak more correctly, 
the most intimate knowledge of the petrifactions or fossils con- 
tained in each of the formations, is not indispensable for present- 
ing a complete and truly geognostical picture. It is with the study 
of formations as with that of organic beings. Botany and zoology, 
which are now considered under a higher point of view, are no 
longer confined to the investigation of some external characters 
distinctive of the species ; these sciences investigate the whole of 
vegetable and animal organization. The characters taken from 
the forms of the shell, suffice to distinguish the different species 
of acephalous testacea ; but, for all this, could the knowledge of 
the animals which inhabit these shells be regarded as superflu- 
ous ? Such is the connexion of phenomena, and of their natu- 
ral relations, that, if some be neglected, there is produced not 
only an incomplete image, but also a false one. 
In the case of the conformity of position, there may be iden- 
tity of mass (that is to say, of mineralogical composition) and 
diversity of petrifactions, or diversity of mass and identity of pe- 
trifactions, The rocks /3 and /s', placed at great horizontal dis- 
tances, between two identical formations « and y, either belong 
to the same formation, or are of parallel formations. In the 
former case, their mineral composition is similar ; but, from the 
distance of the places, and the effects of climate, the organic re- 
mains which they contain may differ considerably. In the other 
case, the mineralogical composition is different, but the organic 
remains may be analogous. I am of opinion that the words 
identical formations , parallel formations , vindicate the confor- 
mity or non-conformity of mineralogical composition ; but that 
they determine nothing with regard to the identity of petrifac- 
tions. If it is pretty probable that the deposits and /s', placed 
at great horizontal distances between the same rocks * and y, 
have been formed at the same period, because they contain the 
same fossils, and an analogous mass ; it is not equally probable, 
on the other hand, that when the fossils are distinct, the periods 
