The more recent calcareous, or calcium carbonate, deposits that make up the tufa formations are closer to the bottom and lighter in color.
钙质或碳酸钙越近现代，所构成凝灰岩地层的沉积物越靠近底部，颜色也比较浅。
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This pressure can ensure the blood from the bottom up to accelerate the return, cleaning vascular excess deposits, not be caused by vascular pressure caused the blood is not smooth.