Vill PREFACE. 
reliable guides. They are the criteria by which he judges of the ages and 
relative positions of the rocks containing them, and thus are labels written upon 
these rocks, which to one who has learned the language are easily read, and are 
infallible. All over the world governments, societies, and individuals are 
spending large sums of money for the diffusion of just such knowledge as is 
contained in our paleontological reports, and there is little doubt that sooner or 
later the extremely interesting material which has been gathered for the third 
volume on Paleontology will be asked for and given to the public by the 
authorities of the State. 
J. S. Ne 
