vi INTRODUCTORY NOTE. 
sive region of the western edge of our continent. This paper also offers 
a worthy and most desirable supplement to the “Botany of California,’ 
of which one volume has been already published, while the other and 
concluding one is now in the press. All the volumes and memoirs above 
mentioned are to be received as a continuation, in part, of the work of 
the Geological Survey, stopped by the Legislature in 1874. Permission 
has been given to the late State Geologist by the Board of Regents of 
the University of California, in whose hands the matter was left, to con- 
tinue the publication of the Survey so far as it was in his power to do 
so; and in this somewhat arduous undertaking he has received valuable 
assistance from some of the liberal-minded citizens of San Francisco, to 
whom he takes this opportunity of tendering his best thanks. 
J. D. WHITNEY: 
