In a few yards they were off the causeway; the coach, striking deep water, settled like a boat, and turned over on its side, with the leaders swimming for their lives.

As for the wheelers, they were pulled down with the vehicle, and were almost drowning in their harness.
Cool as a cucumber, Blake had turned to the girl.

"Can you swim ?" he said.

And she answered him as cooly, "Yes, a little." "Well, put your hands on my shoulders, and leave everything to me." Just then the coach settled over with one final surge, and they were in the water.
Away they went with the roaring current, the girl clinging fast to his shoulders, while he gave his whole attention to dodging the stumps and snags that were showing their formidable teeth above water.

For a while she was able to hold on.