. . . "while entrenching" . . . "entrenchment" . "entrenched" . . . "incised meander" . "incised meandering" . . . "entrenched valleys" . "entrenched river" . "entrenched itself" . . . "Entrenched river" . "maintain its ancient course" . . . . . "Entrenched river" . . "superposed or antecedent stream" . "entrenched meanders" .