NOTICES OF BOOKS. 119 



to the hereditary character of specific forms, as derived from the Egyp- 

 tian sculptures, adding, that stability (permanence) of form is the hypo- 

 thesis that must present itself first to any unprejudiced observer, whilst 

 it is for those who demand a constant renewal of forms to prove their 

 position; and as to those geologists who maintain that every well- 

 marked geological epoch has different plants as well as different 

 animals, M. de Candolle thinks that their assumption is too absolute.* 

 Eetaining the proofs of the antiquity of existing species, the weight 

 of the evidence rests, more or less directly, on two main classes of facts : 

 of these, to the first belong the imbedded remains of plants, believed to 

 be specifically identical with existing ones, in bogs and in the sea, whose 

 submersion or imbedding in all cases precedes the historical era, and in 

 some eases, owing to the bulk or character of the superincumbent soil, 

 or to the nature of the animal remains imbedded with them, ma}? fairly 

 be considered as preceding the existing geological condition of the 

 country. Sir Charles Ly ell's 'North ximerican Travels' afford M. de 

 Candolle the best cases in point, and his other works many more. A 

 unique case is that of the identification, by M. Brongniart, of the nut 

 of a species of Hickory found in the pleiocepe beds of Europe, with 

 that of a North American species. M. de Candolle however adds the 

 caution, that this does not prove specific identity, as the flowers, leaves, 

 etc. of the plants may be different.! 



* Upon this point the views of- our hest English geologists would certainly agree 

 with M. de Candolle's, and we would add that there is still much to he learnt upon 

 this subject from the distribution of plants. The difference between the existing 

 Moras of Europe and Australia is the equivalent of two geological epochs, so distiuct 

 that a palaeontologist would demand the lapse of an indefinite number of intervening 

 ceutui'ies between the times during which each flourished, supposing them to be 

 superimposed, or inclose proximity. But though Europe and Asia are not juxta- 

 posed, Australia and New Zealand are, and they present analogous differences, as 

 do South-east and South-west Australia. If allowance is not made by geologists 

 for possible great differences between the inhabitants of adjacent countries, still less 

 is often granted for local distribution. The species and genera of one Flora are so 

 distributed that contiguous spots present different assemblages, and it is these local 

 causes that lead to the imbedding of fossils that also detennine the kind of plants to 

 he imbedded. Again, fossils are too often regarded as affording absolute proof ot 

 the character of the Flora to which they belonged, whereas they may be only indica- 

 tions of the prevalence of a species, the genus or order of which ia otherwise absent 

 or extremely rare at the same epoch ; for instance, it is often the case that one 

 species of Fern is so abundant over an area where Ferns form a small proportion of 

 the Flora, that it would probably be found in every bed of fossils ; whilst Com/era, 

 which form a larger proportion of the Flora of Tasmania than any equivalent area, 

 are so scarce in individuals there that they would appear very rarely amongst other 



fossil remains. , t^ i i t- t i i • u 



t This reminds us of a point much insisted upon by Edward Forbes, and which 



