Yahya related to me from Malik that Abu Jafar al-Qari said, "Isaw Abdullah ibn Umar quickly brush away the small stones from theplace where he was going to put his forehead as he was going down intosajda." (RU)
USC-MSA web (English) reference: Book 9, Hadith 45 (RU)
Arabic reference (RU): Book 9, Hadith 376 (RU)