Forest Canyon, the Fall River Valley, the Cache la Poudre River Valley and the Kawuneeche (Colorado River) Valley are perhaps the best examples of U-shaped valleys.
(Forest Canyon, the Fall River Valley, the Cache la Poudre River Valley and the Kawuneeche (Colorado River) Valley; are perhaps; the best examples of U-shaped valleys)
Forest Canyon, the Fall River Valley, the Cache la Poudre River Valley and the Kawuneeche (Colorado River) Valley
are perhaps
the best examples of U-shaped valleys