552 Jil Wis etl IUSIBy A INIEGS) 
twenty-nine miles. The seacoast traverses it diagonally form- 
ing the southwest boundary. The region is one of complex 
structural features and has represented within it nearly all the 
sedimentary formations characteristic of the Coast Ranges as well 
as a great variety of igneous rocks. As far as the writer has 
yet studied the Coast Ranges no other region of equal area has 
been found to contain so much of geologic interest. 
More than six months of the past year has been devoted to 
field work?‘ in this region besides several reconnoissances in for- 
mer years. It is expected that a part of the results will appear 
in the form of a folio of the United States Geological Survey, 
and a complete report later in one of the Annuals. 
TOPOGRAPHIC FEATURES. 
The main topographic features have a northwesterly and 
southeasterly direction. The Santa Lucia is the highest and 
most important mountain range, extending parallel with the 
Coast across the center of theyarea surveyed.) Onethessoutn 
forming the high ridge terminating on the ocean in Point 
Buchon is the San Luis range. Crossing the northeast corner 
of the area is the northern extension of the San Jose range. 
All three ranges are traversed by narrow canyons which open 
upon broad and almost level or undulating valleys which extend 
in a northwest and southeast direction between these three 
important mountain blocks. The area is thus divided into two 
portions with sharply contrasted cycles of development, that is, 
recent mountain ranges with steep slopes and traversed by nar- 
row canyons, and broad valleys in an advanced stage of base- 
leveling. 
The Santa Lucia range forms the divide between those 
streams which flow directly into the Pacific Ocean and those 
which drain into the Salinas River. The valley of the upper 
portion of this river crosses the region surveyed between the 
tThe writer was aided in the field by Mr. F. E. Harvey, a senior student in 
Stanford University, and Mr. Robert Moran of San Luis Obispo, both enthusiastic 
students. 
