On the southern coast of Cape Inubosaki (Choshi City, Chiba Prefecture), sea cliffs carved by the violent waves of the Pacific Ocean can be seen over a length of about 10 kilometers. The cliffs, named “Byobugaura,” are made of the “Inubo Group,” a stratum deposited between 3 million and 300,000 years ago, and are mainly composed of fine-grained grayish-white siltstone. (In addition, coarse-grained sandstone can be found in the lower part of the Inubo Group, and orange to brown Kanto loam layers can be found at the top of the cliffs that cover the Inubo Group.)
The layered strata dip gently toward the northwest, reaching a depth of 1,000 to 2,000 meters in the central part of the Kanto Plain and around Tokyo.
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