However, the Helcionellids, which first appear over  in Early Cambrian rocks from Siberia and China, are thought to be early molluscs with rather snail-like shells.
haʊˈɛvɚ, ðə hˈɛlʃənˌɛlɪdz, wˌɪtʃ fˈɜːst ɐpˈɪɹ ˌoʊvɚɹ ɪn ˈɜːli kˈæmbɹiən ɹˈɑːks fɹʌm saɪbˈiəɹɪə ænd tʃˈaɪnə, ɑːɹ θˈɔːt təbi ˈɜːli mˈɑːlʌsks wɪð ɹˈæðɚ snˈeɪllˈaɪk ʃˈɛlz.