ðɪ ˈɛkoːɹdʒən ɪz ˌʌndɚlˈeɪn baɪ ʌŋkənsˈɑːlᵻdˌeɪɾᵻd ɡlˌeɪsɪəflˈuːvɪəl dᵻpˈɑːzɪts, sˈɪlti ɐlˈuːviəm, sˈɪlti ænd klˈeɪi mɚɹˈiːn sˈɛdɪmənts ænd ɡlˈeɪʃəl tˈɪl.
The ecoregion is underlain by unconsolidated glaciofluvial deposits, silty alluvium, silty and clayey marine sediments and glacial till.