"That must be a deep spring, I don't see how it could dry up," he said.

"It must be a deep spring to be still running," Joseph said.

One object of the group's research was to prove that the deep underground springs were truly isolated from the world above.

We must look to the deep springs, I think.

As time passed; they found deeper springs of strength to sustain them.

The deep springs are likely to be radioactive, too.

The water felt cool from the deep spring that was its source.

A deep, almost still spring, it had a surface area no larger than his palm.

Beyond it ran a deep cold spring, a small river.

There was a deep spring in a hollow, the water not flowing out but rather keeping to itself.