nˈætʃɚɹəli əkˈɜːɹɪŋ dᵻpˈɑːzɪts ʌv bɪtˈuːmɛn ɑːɹ fˈɔːɹmd fɹʌmðə ɹᵻmˈeɪnz ʌv ˈeɪntʃənt, mˌaɪkɹəskˈɑːpɪk ˈælɡiː dˈaɪəɾəmz ænd ˈʌðɚ wˈʌnslˈɪvɪŋ θˈɪŋz.
Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae (diatoms) and other once-living things.