BLUE MUD. 75 



in the later periods they become both more 

 numerous and more varied in proportion as 

 they approach nearer and nearer to our own 

 time. 



So too, in the days when Mr. Darwin first 

 took away the breath of scientific Europe by 

 his startling theories, it used confidently to be 

 said that geology had shown us no interme- 

 diate form between species and species. Even 

 at the time when this assertion was originally 

 made it was quite untenable. All early geo- 

 logical forms, of whatever race, belong to 

 what we foolishly call ' generalised ' types : 

 that is to say, they present a mixture of fea- 

 tures now found separately in several different 

 animals. In other words, they represent 

 early ancestors of all the modern forms, with 

 peculiarities intermediate between those of 

 their more highly differentiated descendants ; 

 and hence we ought to call them 'unspe- 

 cialised ' rather than ' generalised ' types. For 

 example, the earliest ancestral horse is partly 

 a horse and partly a tapir : we may regard 



