Abu Dawud Book 9, Hadith Number 2817.
Chapter : On slaughtering an animal with a sharp white stone used as a knife flint.
Narated By Ata’ ibn Yasar : A man of Banu Harith was pasturing a pregnant she-camel in one of the ravines of Uhud, (he saw that) it was about to die; he could find nothing to slaughter it; he took a stake and stabbed it in the upper part of its breast until he made its blood flow.
He then came to the Prophet (PBUH) and informed him about that, and he ordered him to eat it.