Fig 4 from The Origin and Growth of Ripple-mark.jpg
Hertha Ayrton
en
Fig 4 from The Origin and Growth of Ripple mark, Sand ripples, Hertha Ayrton
commons
ja
リップル・マークの起源と成長図の図4、砂の波紋、ヘルタ・エアトン
commons_translated
ripple mark ripple old growth rippled