solid bottom

This is solid bottom ground and bed rock, safe for chain-cable holding; safe for building upon, however high the superstructure.

He found excellent moorage in five fathoms' depth of water, with a solid bottom of hard granite, which afforded a firm hold.

We have dug the hole deep so that we may commence in the next chapter to lay the foundation on solid bottom.

When a pebble is dropped into this opening a dull thud can be heard, as though the stone had not struck solid bottom.

For this was no question of looking down a half-mile, a mile, or even five, to some solid bottom.