Maliks Muwatta Book 20, Hadith Number 258.
Yahya related to me from Malik from Muhammad ibn Amr ibn Halhala ad-Dili from Muhammad ibn lmran al-Ansari that his father said that Abdullah ibn Umar came upon him while he stopped for a rest under a tall tree on the road to Makka, and he said, “What has made you stop under this tall tree?” He replied that he sought it’s shade. Abdullah ibn Umar said, “Anything besides that?” and he said, “No, that was the only. reason he stopped for a rest,” and Abdullah ibn Umar said, “The Messenger of Allah, may Allah bless him and grant him peace, said, ‘If you are between al-Akhshabayn (which are two mountains) near Mina,’ indicating the east with his outspread hand, ‘you will find a valley called as-Surar with a tree in it beneath which the umbilical cords of seventy prophets have been cut.'”