558 Hl. W. FAIRBANKS 
The sandstone is characteristically thick bedded and in gen- 
eral shows little if any metamorphism, except in the vicinity of 
eruptive iasses. It disintegrates readily, forming a rather 
heavy soil. It is almost everywhere, however, seamed and fis- 
sured, while the softer, shaly strata are often crushed and dis- 
torted. The five-mile section along the coast, north of Port 
Harford, exhibits the relative proportion of sandstone in the 
series. Along this stretch the strata stand vertical and with the 
exception of thin layers of shale and several lenticular strata of 
jasper consists entirely of sandstone. The apparent thickness 
of this section is fully 10,000 feet, but whether this represents 
the total thickness of the Golden Gate series is not certain. 
The outcrops of jasper are very abundant over the whole of 
the region occupied by the Golden Gate series, and as they 
weather away much more slowly than the sandstones form the 
most prominent of the smaller topographic features, rising often 
as jagged or rounded knobs above the rolling contour of the 
hills. There are at least half a dozen important horizons, which, 
though apparently not confined to any one portion of the series 
yet are mostly aggregated toward what seems to be the basal 
portion. The strata of jasper are of very irregular dimensions 
swelling and pinching and often appearing as isolated lenses, 
but rarely exceeding 100 feet inthickness. The basic intrusives 
so numerous in the Golden Gate series occur mostly in that 
portion occupied by the jasper beds, the latter generally being 
reddened and often involved in the erupted masses. The con- 
tact of the jasper with the sandstone as well as the easy parting 
of the jasper bands undoubtedly facilitated the passage of the 
molten matter. The organic nature of the rock is indicated by 
the minute radiolarian skeletons in which the structure can often 
be seen with a pocket lense. 
Scattered over the area occupied by the Golden Gate series 
occur prominent outcrops of a metamorphic schistose rock 
having a predominantly bluish tint. Owing to the general 
covering of soil the relations of these rocks are not always 
shown but where exposures are sufficiently good they appear to 
