VUl 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. N. 



