But though the workmen kept on building up the cribs, they did not seem to grow any higher. As fast as the new logs were added the weight carried them down deeper into the water. Finally they were sunk into the mud at the bottom of the trenches by filling them with tons upon tons of broken rocks, and when they were firmly imbedded they were built up to the proper height with more logs. In some places these cribs are higher than an ordinary city house, and considerably wider at the bottom. Imagine a log cabin bigger than a house, and you have a good idea of what these cribs would look like if entirely out of water. When finally settled in place the outside edges were trimmed with smooth-cut timbers, and the work of filling in began. A little railroad was built along the tops of the sunken cribs and up the side of the hill, where a lot of blasting and digging was going on. Dummy-cars pulled by mules were loaded with rocks and earth, and dumped into the great gap between the cribs and the shore. Many thousands of tons of dirt and rocks were thrown in here before the big opening was filled up. [Illustration: WHERE THE CRIBS HAVE SLID OUT OF PLACE.] But the engineers had made a serious mistake in planning this part of the boulevard, and the weight of the filling behind them pushed some of the cribs out into the water. Far down under the soft muddy bottom there is hard rock, and this shelves out rapidly toward the middle of the river; so when the great weight was filled in behind the sunken cribs, the mud, cribs and all, slid out in places away from the shore. Some parts have moved as much as eight feet at the top, and apparently much more at the bottom, and before the great speedway can be finished, this work will have to be repaired, and the outer edge moved back out of the channel of the river. Just below the bridge a great rocky promontory jutted out into the way like a cape, and nearly a hundred thousand cubic yards of rock were blasted away to make room for the boulevard. When the workmen got down to the level of the water, submarine drills had to be used for the blasting. This work, too, was very interesting. Divers in rubber suits with glass eyes were sent down under the water to fix the drills in position, and then the holes were bored from the floats above. When they had been sunk deep enough, the divers went down again and fixed the charges of powder that blasted out the rocks. It was like a small earthquake and water-spout combined when one of these blasts went off.