Extending from Canyon to Silverton, Palo Duro Canyon was formed primarily by water erosion from the Prairie Dog Town Fork of the Red River, which began to carve the canyon less than one million years ago.
(Extending from Canyon to Silverton; was formed; primarily by water erosion from the Prairie Dog Town Fork of the Red River) (the Prairie Dog Town Fork of the Red River; began; to carve the canyon less than one million years ago) (the Prairie Dog Town Fork of the Red River; to carve; the canyon; T:less than one million years ago)
Extending from Canyon to Silverton the Prairie Dog Town Fork of the Red River the Prairie Dog Town Fork of the Red River
was formed began to carve
primarily by water erosion from the Prairie Dog Town Fork of the Red River
to carve the canyon less than one million years ago
the canyon T:less than one million years ago