Photos:: Artifacts uncovered by drought at Butte County’s Lake Oroville

Severe drought conditions are evident as hundreds of house boats are dwarfed by steep banks that show the water level down 160 feet from the high water mark at Bidwell Canyon Marina on Lake Oroville in June.  (Allen J. Schaben / Los Angeles Times)

A lone house boat is dwarfed by new, uncovered islands that show the water level down 160 feet from the high water mark at Lake Oroville.  (Allen J. Schaben / Los Angeles Times)

California State Parks Ranger Bryan Taylor looks at ancient Native American bedrock mortars worn over ages by the grinding of acorns for signs of disturbance or theft.  (Allen J. Schaben / Los Angeles Times)

Bryan Taylor, left, California State Parks Ranger, along with Kim Preston and Doug Richards, right, both site stewards for the California Archeological Site Stewardship Program, look at ancient Native American bedrock mortars.  (Allen J. Schaben / Los Angeles Times)

A detail of an ancient Native American bedrock mortars visible now because California’s severe drought conditions.  (Allen J. Schaben / Los Angeles Times)

A house boat is dwarfed by steep banks that show the water level down 160 feet from the high water mark at Lake Oroville.  (Allen J. Schaben / Los Angeles Times)

Officials say Lake Oroville is only at 42% capacity and is likely to get worse, but not as bad as the drought of 1976-77.  (Allen J. Schaben / Los Angeles Times)