420 B. WILLIS — SOME COAST MIGRATIONS, CALIFORNIA 



higher slopes, including acute peaks, sharp ridges, and wide ravines. A 

 later is suggested in the lower slopes by broad spurs, canyons, steep 

 scarps, terrace remnants, and terraces, the sequence leading down to the 

 present ocean level. 



The aspect of the higher slopes, above 3,200 feet, more or less, above 

 sea, is that of advanced maturity. All forms are acutely developed. 

 Rock masses are sharply distinguished according to resistance to erosion. 

 There are practically no areas of gentle slope which might be considered 

 as remnants of an earlier topographic surface. 



At a certain elevation — that is, probably not far from 3.200 feet above 

 sea — a great number of summits, ridges, and spurs fall into a level with 

 the horizon. Nearly flat surfaces, which, though of moderate extent, 

 are nevertheless inconsistent with existing conditions of energetic cor- 

 rosion, survive here and there. This expanse of elevations is interpreted 

 as evidence of an early lowland, a hilly lowland possibly, possibly a 

 plain, above which the greater heights stood as monadnocks. 



Below this certain elevation of approximately 3,200 feet the slope of 

 the range toward the Pacific is comparatively gentle down to 2,000 feet 

 or less above sea. Long spurs jut south west ward, descending at easy 

 grades, or from bench to bench by steps. Between the spurs deep wide- 

 gaping ravines are sunk, V-shaped. A pproaching the ocean they become 

 canyons. This description applies particularly to the spurs abreast of 

 Gamboa point and to the Devils canyon. At 2,000 feet above sea, or 

 thereabouts, the spurs end, some in prominent knobs, others in terrace 

 remnants (see plate 29), and thence to the ocean the descent is distinctly 

 steeper than it is from above. Locally for 1,500 feet the slope is probably 

 as steep as 35 degrees. No lower spurs jut ocean ward, but where canyons 

 trend parallel to the coast narrow divides separate them from the Pacific. 

 On these divides terrace remnants are preserved, as may be seen at Posts, 

 between Big Sur valley and the ocean, at an elevation of 800 to 900 feet, 

 and at the mouth of Devils canyon, 1,000 to 1,150 feet above sea. Other 

 less conspicuous bits of terrace hang here and there on the steep slope. 

 The final descent to the sea is locally by a precipice against whose foot 

 the surf dashes. Elsewhere a terrace intervenes, 20 to 80 feet above sea, 

 affording a strip of pasture land which may attain a width of 300 yards. 

 This lowest terrace bears a heavy deposit of boulders and gravel, a con- 

 glomerate probably of Pleistocene age. Its face is usually too steep to 

 climb from the beach (see plate 27). 



As a working hypothesis, the writer offers the following reading of this 

 physiography of the Santa Lucia range. The site of the Santa Lucia 

 range was submerged in early Miocene (?) time and may have been so 

 throughout later Miocene epochs, but a land area lay west of it. During 



