IV PREFACE. 
studied. As the stereotyped plates of the omitted prelim- 
inary reports are preserved, new editions may be ordered 
should there be a demand for them. A change has also been 
made in the size of the volume by decreasing the size of the 
margin, which, it is thought, will make the volume a more 
convenient size, both for library use and for sending through 
the mails. 
JOHN R. PROCTER, 
State Geologist. 
