An interval followed in the northern part of the Pyramid Peak quadrangle where no important volcanoes were located, but they appear again in full force in Alpine County.

Round Top, attaining an elevation of 10,430 feet, and the adjacent peaks, were the sources of the enormous flows which covered a large part of Eldorado County.

Still another volcanic complex with many eruptive vents is that situated in the western part of Alpine County, near Markleeville, which culminates in Highland Peak and Raymond Peak, the former almost reaching 11,000 feet.

The total thickness of the volcanic flows in this locality is as much as 4000 feet." It is to these breccias we owe the volcanic appearances in the Truckee River Canyon, a few miles before reaching the Lake.

There are several layers of the andesites breccias at the head of Bear Creek Canyon, above Deer Park Springs.
"None of the craters," says Lindgren, "of these volcanoes are preserved, and at the time of their greatest activity they may have reached a height of several thousand feet above the present summits.".