In geology, a claypan is a dense, compact, slowly permeable layer in the subsoil having a much higher clay content than the overlying material, from which it is separated by a sharply defined boundary. Claypans are usually hard when dry, and plastic and sticky when wet. They limit or slow the downward movement of water through the soil. This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ... Óģ Ķ ķ Ļ ļ Ņ ņ Ŗ ŗ Ş ş Ţ ţ Ć ć Ĺ ĺ Ń ń Ŕ ŕ Ś ś Ý ý Ź ź Đ đ Ů ů Č č Ď ď Ľ ľ Ň ň Ř ř Š š Ť ť Ž ž Ǎ ǎ Ě ě Ǐ ǐ Ǒ ǒ Ǔ ǔ Ā ā Ē ē Ī ī Ō ō Ū ū ǖ ǘ ǚ ǜ Ĉ ĉ Ĝ ĝ Ĥ ĥ Ĵ ĵ Ŝ ŝ Ŵ ŵ Ŷ ŷ Ă ă Ğ ğ Ŭ ŭ Ċ ċ Ė ė Ġ ġ İ ı Ż ż Ą ą Ę ę Į į Ų ų Ł ł Ő ő Ű ű Ŀ ŀ Ħ ħ Ð ð Þ þ Œ œ Æ æ Ø ø Å å Ə ə – — … [] [[]] {{}} ~ | ° § → ≈ ± − × ¹ ² ³ ‘ “ ’ ” £ € Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... Impact of a drop of water Water is a chemical substance that is essential to all known forms of life[1]. It covers 71% of Earths surface. ... For the American hard rock band, see Soil (band). ...