Book Notices. 505 



is almost certain that at this period there was land connection between 

 India and Southern Africa by way of Madagascar. This will account 

 for the remarkable similarity in many of the animals inhabiting these 

 •countries. 



The purity and thickness of the chalk deposit are hard to explain. 

 It has been suggested by an eminent geologist that in addition to 

 its partially organic origin it may have been formed as a chemical 

 precipitate of carbonate of lime. The origin of flints in the chalk has 

 been a subject of great interest. It is believed that they were originally 

 an integral portion of the rock itself, which was then a slightly 

 silicated limestone, and that the silica has separated out by segregation, 

 a sponge spicule or an echinoid shell being the nucleus around which 

 the segregating process has taken place. 



The conciseness and clearness with which this book is written is 

 worthy of notice- A large amount of information is presented in a 

 small bulk (220 pp,). The illustrations are excellent, while here and 

 there the humor of the writer enlivens the discussion of dry facts. 



Rosalind Watson. 



