Annual report of the United States Geological Survey to the Secretary of the Interior . re, no doubt, to the regularity of the winds and the sand small ridges were seen also at other places, but they M ere lessregular and extensive. Several miles north of the mouth of TillamookBay such ridges inclosed lakes of considerable size close to the beach,and the only outlet was by filtration through the barrier. The picturesque features of the coast are found not so much in itsbeaches as in its headlands. Of these, Tillamook Head, False Tille-mook, and Meares Point are good examples. Al
Annual report of the United States Geological Survey to the Secretary of the Interior . re, no doubt, to the regularity of the winds and the sand small ridges were seen also at other places, but they M ere lessregular and extensive. Several miles north of the mouth of TillamookBay such ridges inclosed lakes of considerable size close to the beach,and the only outlet was by filtration through the barrier. The picturesque features of the coast are found not so much in itsbeaches as in its headlands. Of these, Tillamook Head, False Tille-mook, and Meares Point are good examples. All are composed ofigneous rocks, with cliffs against the surf, which break the continuityof the beach in each case for several miles. The northern end ofMeares Point is shown in PI. VI. A sheet of columnar basalt occursnear high-tide level, and enables the waves to cut out caverns of con-siderable dimensions. These in time enlarge and join, forming archeswhich when broken leave pillars and ledges, such as are seen on theright in the illustration, to mark the line of an earlier HISTORICAL NOTES. 451 The only headland of sedimentary rock seen on the coast by thewriter is Otter Rock, which is composed of thin-bedded, yellowish Mio-cene sandstone. It is firmer than its neighbor, and sternly resists thedash of the waves, but is gradually giving way under their unceasingattack. One of its principal ledges, 40 feet above the water, is inplaces full of holes, made by the rock oyster at a time when the laudstood 40 feet lower than now. Potholes are common on the surface,and from the north side a cave enters the rock, its roof having tumbledin and formed a great pit, known as the Caldron. It is 40 feet deepand of equal diameter. The debris at its bottom is swept away bythe waves, and at low tide it can be entered from the beach. HISTORICAL NOTES. The earliest definite information concerning the geology of thatportion of the country indicated as belonging to the Coast Rangeof Orego
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