Dinosaur National Monument: Split Mountain And The Green River

The Split Mountain Campground, Day Use Picnic Area Along the Green River At Dinosaur National Monument

When I told people we were going to Dinosaur National Monument this summer, all anyone ever talked about were the dinosaur bones and fossils in the Wall Of Bones at the Quarry Exhibit Hall. Everything was about dinosaurs and we were thrilled. But then we got to Dinosaur National Monument in Vernal, Utah and found out that isn’t exactly the case.

While Dinosaur National Monument is all about dinosaurs and you can see 1,500 dinosaur fossils in the the quarry wall, there is so much more to do and see, like the Swelter Shelter petroglyphs and the Fremont petroglyphs, the Turtle Rock and Elephant Toes Butte rock formations, the rainbow colors of the Morrison Formation, the Josie Morris Homestead and Box Canyon Trail, and the Split Mountain Campgrounds and the Green River.

All of the dinosaur related activities and sights are easily accessible from the Quarry Visitor Center and all of the other things are easily accessible off Cub Creek Road on the Tour Of The Tilted Rocks, a 24 mile round trip scenic drive.

Tour Of The Tilted Rocks travels on Cub Creek Road, but temporarily leaves the main road to travel to the Split Mountain Campground and back. On this short side trip, there are absolutely incredible views with the impressive, uneven, rugged ridge line of Split Mountain towering above Dinosaur National Monument in the background.

Split Mountain Viewpoint in Dinosaur National Monument
The Split Mountain scenic viewpoint along Cub Creek Road at Dinosaur National Monument.

Some of the things you’ll see along this portion of the Tour Of The Tilted Rocks scenic drive are:

Split Mountain Campground

Split Mountain is named for the fact that the Green River has split it in half. At the scenic overlook, you can see panoramic views of the Cub Creek Valley with Split Mountain on the left and Blue Mountain on the right. Native cottonwood trees shade the campground along the Green River. Sitting at 5,000 feet elevation, rain and snow provide less than 10 inches of water to this area each year.

The Split Mountain Group Campground is located on the banks of Green River at an elevation of 4,800 feet. The campground is near the Dinosaur Quarry, where you can see 149 million year old dinosaur bones still encased in the rock. Right beside the campground is the Split Mountain Boat Ramp where river rafters come off the Green River after rafting trips through Dinosaur National Monument’s canyons.

Morrison Formation

As you’re driving toward the Split Mountain Campground, you’ll see gorgeous hills banded with shades of gray, red, purple, and brown. These colorful layers identify the Morrison Formation, a group of rock layers that occur throughout the region.

The Morrison Formation is a rock unit from the Late Jurassic period — 155 million years ago-148 million years ago. It extends throughout the Western United States and can be seen at the Carnegie Dinosaur Quarry in Utah and and Dinosaur Ridge in Morrison, Colorado.

The Morrison Formation often contains fossils of dinosaurs such as Camarasaurus, Diplodocus, Apatosaurus, Stegosaurus, Allosaurus, and others. When paleontologist Earl Douglass discovered the quarry in 1909, the Morrison in other areas had already proven to be rich in fossils. In addition to finding new species, paleontologists have found many exceptionally well preserved specimens of previously discovered dinosaurs.

The Colorful Layers Of Rock Are Part of the Morrison Formation
The colorful layers of rock in the hill in the foreground are part of the Morrison Formation.

Placer Point Scenic Vista

A short side road leads to bend in the river called Placer Point and gorgeous views of the Green River. The name refers to an effort in the 1930s to dredge and sluice gold from the river bottom, however the gold particles were too fine to extract profitably and the operation eventually folded.

The River Trail, which runs alongside the Green River between Split Mountain Campground and Green River Campground, offers outstanding views of the Green River and Split Mountain. This trail is also one of the best places to birdwatch at the monument.

Placer Point On The Green River In Dinosaur National Monument
Placer Point is scenic vista point at a bend in the Green River at Dinosaur National Monument.

The Geology Of Split Mountain And The Green River

When looking at Split Mountain, you can see layers of tilted rocks — rocks that once were flat, but have been forced upward into an irregular dome shape. The incredible ridges of stone are all that remain of rock layers that once crossed Split Mountain.

At one time, scientists believed that the Green River must have been flowing in its current location before the massive uplift and tilting of rocks, and as the rocks were pushed upward the river cut right through them. But more recent discoveries show that Split Mountain is actually much older than the Green River.

According to the Tour Of The Tilted Rocks print guide…

When the Rocky Mountains uplifted 50-60 million years ago, the Uinta Mountains were also created. Split Mountain and nearby Blue Mountain are foothills of the Uintas, which were once much taller than they are today. For tens of millions of years, the Uinta Mountains shed rock and dirt which completely buried Split Mountain and Blue Mountain. Eventually ancient rivers gave way to the Green River, which began to downcut into the old sediment.

The Green River originally sat in a riverbed thousands of feet above where it flows today. It moved high above Split Mountain that was buried in the dirt. Over time, the river cut through the dirt, eventually reaching the rock of Split Mountain. By then, however, the river was held in place by its deep banks and could not change course, so it cut through the top of Split Mountain. Over time erosion from water and wind removed most of the sediment that buried this area, leaving us with the scenic landscape seen today.

If you look carefully along parts of Cub Creek Road, you’ll see large, fist-size, smooth rounded rocks in the dirt. These unusual rocks were created from the turbulent waters of the Green River and deposited here when the river flowed at that elevation.

Green River Scenic Overlook In The Cub Creek Valley
The Green River winds through Cub Creek Valley and a dirt trail meanders alongside it.

Know Before You Go

  • Split Mountain And The Green River are accessible on the Tour Of The Tilted Rocks Scenic Drive, a 12 mile one-way drive along Cub Creek Road in Dinosaur National Monument.
  • The drive begins at the Quarry Visitor Center located off Highway 149 at 11625 E 1500 Street, Jensen, Utah 84035 in Uintah County.
  • The last two miles of the route are unpaved but well maintained. The last four miles are unplowed in the winter and may not be passable by car December to March.
  • Some other stops along the self-guided Tour Of The Tilted Rocks include the Swelter Shelter petroglyphs, Turtle Rock and Elephant Toes Butte, the Fremont petroglyphs, the Josie Bassett Morris Homestead, and Box Canyon Trail.
  • At the Quarry Visitor Center, pick up the Tour of The Tilted Rocks print guide ($1.00) with information about wildlife, unique rock formations, petroglyphs, and historic sites along the road.
  • The guide will tell you to allow at least one hour for the Tour Of The Tilted Rocks Scenic Drive, but it took us almost three hours because we explored every numbered stop.
  • The Visitor Center is open daily from 8:00 am to 6:00 pm during peak season from late May to mid-September and 9:00 am to 5:00 pm during the off season from mid-September to late May. Dinosaur National Monument is closed on Thanksgiving, Christmas, and New Year’s Day.
  • On the drive down Cub Creek Road and back, there will be many opportunities to get out and take short walks to get a closer look at the points of interest. Also, wildlife may occasionally be seen, including mule deer, bighorn sheep, pronghorn, prairie dogs, and many bird species.
  • Fuel, food, and other services are not available along this route. The nearest services are in Jensen, Utah, seven miles south of the Quarry Visitor Center.

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