Glacial Deltas_.

I have stated that the moraines of Cascade Lake and Emerald Bay glaciers run down to the margin of Lake Tahoe.

An examination of this portion of the Lake shore shows that _they run far into the Lake_--that the Lake has been filled in, two or three miles, by glacial debris.

On the eastern margin of Lake Tahoe, the water, close along the shore, is comparatively shallow, the shore rocky, and along the shore-line, above and below the water, are scattered great bowlders, probably dropped by the main glacier.

But on the west margin of the Lake the shoreline is composed wholly of moraine matter, the water very deep close to shore, and the bottom composed of precisely similar moraine matter.