TERTIARY FOSSILS. 91 



clay, or any other tertiary deposit. Among the 

 millions of organic forms, from corals up to 

 mammals, we find hardly so much as one single 

 secondary species." The exceptions in reality 

 are, the inlusoria of the chalk, and " two or three 

 secondary species," which are said to " straggle 

 into the tertiary system." "Organic nature," he 

 says, " is once more on a new pattern — plants as 

 well as animals are changed. It might seem as 

 if we had been transported to a new planet j for 

 neither in the arrangement of the genera and 

 species, nor in their affinities with the types of an 

 older world, is there the shadow of any approach 

 to a regular plan of organic development." Now 

 the almost total break in the organic creation here 

 insisted upon, occurs ia the interval between the 

 extensive deposits of the secondary formation, 

 and the comparatively isolated deposits of the 

 tertiary-. It is an interval which the lithological 

 arrangements clearly indicate to have been longer 

 than any of those between the other formations, 

 during which minor changes of organic creation 

 had taken plac€. It is simply, then, a period 

 not represented by strata or by fossils ; while it 

 elapsed, the continual advance of the organic 

 world proceeded to a point at which nearly all 



