\AQUINA BAY JETTIES. Yaquina Bay is a narrow estuary some 20 miles long, situated on the Oregon coast 115 miles south of the Columbia River. In its natural condition the harbor throat lay between a rocky headland on the north and a low sandy point on the south. The channel discharged into the ocean over a low sandy bar, and was narrow, uncertain of alignment and depth, and bordered by sands upon which there Were constant breakers. The plan of improve ment finally ailopted consisted of two jetties starting at the harbor throat, about 2300 feet apart, and converging to a distance apart of 1000 feet; the north jetty being 2300 feet long and the south jetty 2600 feet long. Both jetties are rubble-stone mounds. In the case of the south jetty, which rests on sand, the rubble mound is supported on a brush mattress about 4 feet thick, but the mound of the north jetty built on launching ways on shore, towed into position behind the guide-piles, and sunk by load ing them with stone. After the mattress-work
was thoroughly settled, the sea end of each jetty was surmounted by a capping of concrete blocks. Since the original construction the jetties have been considerably added to and repaired. in 1599 the United States Army Engineers sub mitted plans for the construction of jetties at the mouth of the Southwest Pass of the Missis sippi River, but no actual work had been begun at the end of 1900. A rissum6 of this proposed improvement and of the previous work on the South Pass by William Starling, United States Engineer Corps, was published in Engineering rues (New York) of Amzust 2:3 and October 4, 1900. and from this the accompanying cuts are abstracted. See Mississippi RIVER.