57 
auxiliary fault cracks accompanying the main fault-trace in Sonoma and Mendocino 
Counties, which it greatly resembles in surface characteristics. Another line of some prom- 
inence was discovered near the mouths of Humboldt Creek and Wood Gulch. As fig. 11 
indicates, this fault-trace, D, follows for some distance along Wood Gulch, then crosses 
over to the little gorge of Humboldt Creek (plate 318), which it follows out to its mouth. 
The divide at D has a marked depression along the line of faulting. 
THE EARTH MOVEMENT ON THE FAULT OF APRIL 18, 1906. 
The fence cross- 
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Telegraph Hill 
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Pt. Delgada 
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Scale in feet (approx.) 
() 1000 2000 3000 4000 5000 
(LE USGA pee eal | ee i ee 

Fig. 11.— Map of country north of Shelter Cove, Humboldt County, showing 
auxiliary faults in relation to main fault. 
ing it shows no signs of horizontal shifting. It was not learned whether or not it has 
been repaired since the quake. Tracing it to the south up over the grassy hills, it is 
found to disappear somewhere near the head of the little gulch shown on the map. A 
third line was found along the wagon road at EH, following an old fault ridge descend- 
ing the hillside on a slant. Its probable connection with the C line suggests itself. 
In search of the north end of the fault, the following itinerary was made: From Tele- 
graph Hill northeast to the old ridge road, to Albert Boots’ ranch, thence up King’s 
