58 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
Peak and its sister peak to the north; thence to Upper Mattole and Petrolia, via the 
stage road; from Petrolia north across the North Fork of the Mattole River, and along 
the same over the high terraces to the north branch of the North Fork; also westward 
over the hills, north of the river, to the summit of the last hill next to the coast, and 
back along the river; from Petrolia south to the bridge, and up the hills south of the 
town to the top of the great slide existing there; south to Cummings’ ranch; and thence 
across Cooskie Range, between Squaw Creek, Spanish Creek, and Cooskie Creek. It was 
on the high bald spurs between Cooskie, Randall, and Spanish Creeks, close to the coast, 
that old Rift topography was for the first time encountered in this district. Several 
small ponds and ridges are found both on the spurs and close to their bases next to the 
beach. No sign, however, of a fresh disturbance could be found here. 
Finally, an excursion up the coast to Cooskie Creek and then south along the beach 
to Shelter Cove served to encompass the entire area under investigation. A short side 
trip was made up the creek flowing from King’s Peak, but nothing definite could be 
learned regarding the location of the fault. South from Hadley’s ranch at Big Flat, 
the precipitous mountain slopes have been destroyed by extensive and high landslides, 
the dislocated materials of which have frequently advanced out upon the beach in the 
form of glacier-like tongues. The waves at high tide have since nipt these protruding 
masses and truncated them at their ends. Many of the slides occurred apparently on 
the sites of older ones. Their continuity and extent made the discovery of the fault in 
this neighborhood impracticable. The prevalence of great slides along the coast, back 
inland, seems to suggest the possibility of the fault curving along the coast, and 
gradually leaving it south of the Big Flat Ranch. In the belief that this might be the 
case, and that the fault might continue closely along the coast for some distance, to 
reénter farther north, a visit was made to the great slide at Cape Fortunas — the most 
extensive slide along the north coast. No trace of the fault could be discovered here, 
however. No visit was made to Cape Mendocino nor to Needle Rock, a small prom- 
ontory south of Shelter Cove. As seen from the cove, this rock has a pronounced 
saddle suggestive of faulting. Should the fault-trace run thru it, it would have a very 
strongly curved course, parallel with the coast. 
Mr. Matthes’ account of the conditions in the vicinity of Shelter Cove may be supple- 
mented by the following note by Professor A. S. Eakle: 
Shelter Cove appears as a broad slope spreading out and forming a circular coast line of 
about 2 miles in length, with a flat plain 6 to 10 feet above the sea. The ocean is con- 
stantly wearing away the land and no beach surrounds it. Half a mile from the ocean 
the land begins to rise in grassy hills which are abruptly cut off from the high mountains 
behind by a deep canyon. The formation of the cove indicates that it has been broken off 
from the hills above by a huge landslide, perhaps by a former earthquake. The gorge 
which separates it from the mainland is on a line with the general coast. On the south 
side of the cove there are three parallel deep gorges which extend a short distance into the 
hills; and their continuation over the hills is shown by slight depressions which appear to 
have been clefts which have become almost filled with the wash of the hills. Along all 
these lines of weakness fissures were opened and the ground subsided 2 to 3 feet. Cross 
fissures running from one depression to another are also present. The trend of the main 
fissures followed the coast, which is northwest-southeast. On the high crests of the Cooskie 
and King Mountains, which border the coast north of the town, fissures and landslides were 
reported by ranchers looking for cattle, but this region was not visited. In the range south 
of the cove landslides were also reported and a photograph of a large one was taken. The 
rocks of the coast are sandstones and black shales, and the hills and plain of the cove were 
ona of blue and yellow sandy clay, evidently derived from the decomposition of the 
shales. 
