Thus the inland sea of fresh water was formed; though Silvester hints (what is most improbable) that the level of the land sank and formed a basin.

After a time, when the waters had risen high enough, since all water must have an outlet somewhere, the Lake, passing over the green country behind the Red Rocks, came pouring through the channel of the Avon.
Then, farther down, it rose over the banks which were lowest there, and thus found its way over a dam into the sea.

Now when the tide of the ocean is at its ebb, the waters of the Lake rush over these banks with so furious a current that no vessel can either go down or come up.

If they attempted to go down, they would be swamped by the meeting of the waves; if they attempted to come up, the strongest gale that blows could not force them against the stream.

As the tide gradually returns, however, the level of the ocean rises to the level of the Lake, the outward flow of water ceases, and there is even a partial inward flow of the tide which, at its highest, reaches to the Red Rocks.