It had a span of at least 300 feet with a height of about half as much.

It was 1500 or 1800 feet above the river.

Hundreds of cedar trees grew around the arch on the ledges of the huge wall through which it was cut by the action of the elements.
The cliffs everywhere were now becoming more broken, and there was an entrance somewhere from the back country, or it may have been up the canyon, for we discovered remains of tipis and camps with metates or grinding stones, the first evidences of human beings we had seen since the "Moki" wall.

This and the breaking of the cliffs caused us to believe that we were nearing the end of the canyon.

Prof.with Jones and Steward went down-stream on foot for a distance to see what was coming next and found a stretch of very bad water.