PALAEONTOLOGICAL ARGUMENTS 27 



those fossil forms of older strata to those which live 

 at the present time. 



Palaeontology shows in some cases the process of 

 evolution in much detail. I may refer to the researches 

 of Hilgendorf and Hyatt, at Steinheim in Wiirtem- 

 bcrg. They show that while the different species of 

 Planorbis, when considered in the most recent of 

 these strata, are very dissimilar, if the series is studied 

 from the lower to the upper ones, it is easily seen 

 that out of four initial forms, not very different from 

 each other, slightly different forms have in the course 

 of time originated, becoming, as we consider more 

 recent strata, always more diversified, always more 

 different from their ancestors, and from one another. 

 While the origin is the same, the results are quite 

 dissimilar, and if the older strata were wanting, 

 no possible link could be found between the very 

 dissimilar forms which co-exist in the more recent 

 deposits, no line of descent or of relationship could 

 be established. Investigations of less recent elate than 

 those of Hyatt have afforded identical results. In 

 his important work on the Foraminifera, 1 Terquem has 

 shown the forms which are intermediate between types 

 which at first glance seem very dissimilar ; and Rupert 

 Jones more recently, in his " Remarks on the Fora- 



1 Recherches sur les Foraminifcrcs du Lias du Dtpartement de la 

 Moselle. 1858-1866, 



