SRO DIES AN TTE NEOCENE OF CALIFORNIA. 447 
steeply sloping foothills, at levels varying from 100 to 200 feet 
above sea level and slope gently toward the bay or sea.- On the 
bay side these extend to the water’s edge, and then are continued 
without change of grade to the center of the bay, then rise as 
slowly on the other side. On the ocean side wave action: has 
generally cut away the lower part of the slope, leaving cliffs from 
ten to one hundred feet in height. 
Where the contact between this level stretch and the foot- 
hills is not parallel with the shore-line or main axis of the 
mountains it is noticed that the elevation of the contact rises 
toward the axis of the mountains. In some cases this level 
seems to be carried up small streams nearly, if not quite, to their 
heads, forming a marked bench on either bank down through 
which the streams have recently cut. As some question has 
been raised as to whether these terraces are not the results of 
erosion rather than of sedimentation, it may be well to call 
attention to the evidence more in detail. In the first place, these 
terraces and fillings show only horizontal bedding; further, the 
bedding of the strata forming the hillsides is in nearly every case 
more or less highly inclined; and, finally, in nearly every ravine 
one or more contacts were found where the horizontal strata can 
be clearly seen lying upon the highly inclined strata of the 
Merced series. A few of these might!be mentioned.” In the 
head of Wood’s Gulch and in the ravine which heads near it a 
few yards below the Old San Pedro-Colma road, the Merced 
sandstones and thin-bedded gravels have an almost perpendicular 
dip. 'On the edges of these perpendicular beds lie the horizontal 
Quaternary strata, which may be traced continuously down the 
ravine to a point near the crossing of the New San Pedro-Colma 
road; here are found many horizontal pines imbedded in the 
strata. In the cut just north’of the Happy Valley House the 
horizontal Pleistocene overlies strata of the Merced series, having 
av dip of: 35 ..N. 20). EH: 
_. A study of the neighborhood of San Francisco Bay points to 
a recent elevation of the mountains to a level much higher than 
their present. Such a study, as recently pointed out by Professor 
