411 



world ; but the inference is drawn that they must be Cretaceous from 

 their relationship. The vertebrates of the Lignitic iieriod haviug- great 

 powers of locomotion, and being able to live on land as well as in the 

 lakes and marshes of that time, and as we have shown that there was at 

 iio time any important catastrophe or physical changes sufficient to 

 affect them, could well have prolonged their existence far up into the 

 Lignitic group, carrying with them as an inheritance, their Cretaceous 

 characters, so that the important statement of Professor Cope is founded 

 in fact, that during this period a Cretaceous fauna was contemporaneous 

 with a Tertiary flora, establishing an uninterrupted succession of life 

 across what is regarded as one of the greatest breaks in geological time. 



