ðiːz ɹˈɪdʒᵻz mˈɑːɹk ðə nˈɔːɹðɚn ˈɛdʒ ʌvðə ɹˈɛd ɹˈɪvɚ vˈæli, ænd ˈɔfɚɹ ɐ dˈɪfɹənt dʒˌɪəlˈɑːdʒɪkəl ˈætməsfˌɪɹ.
These ridges mark the northern edge of the Red River Valley, and offer a different geological atmosphere.