YELLOWSTONE NATIONAL PARK WELCOME to the Mammoth Hot Spring Terraces, one of Yellowstone’s fascinating natural features! There are several ways to enjoy the terraces—hike the boardwalks or drive the Upper Terrace Loop road, for example. You may wish to drive to the Upper Terrace Loop, drop off members of your party, let them hike down the boardwalk and pick them up at the lower parking area. The maps in this pamphlet will help you decide how you might best enjoy the terraces. The Mammoth Terrace

Hot water is the life of the terraces. Without it terrace growth ceases; the formations weather gray and black, and begin to crumble. Typically the many hot springs gush forth at random, flow a short way, then disappear into a crack or fissure farther down slope. In searching around the Mammoth area old dormant terrace mounds can be found in several places. Although a frequent shifting seems to take place, the records over the past several years indicate that the total flow of water has remained

The Mammoth Terraces are continuously changing. Had you visited the area in the 1930’s, you would have found Blue Spring, Cleopatra, and Angel Terraces to be the feature attractions. Today they stand as gray, lifeless ruins, and newly named springs have succeeded them. Throughout the 1970’s Jupiter and Minerva Springs and parts of Highland Terrace have flowed freely, building delicate and colorful terraces. These clear pools, rimmed by scallops of algae-tinted travertine, have created spectacles

Travertine is deposited as a white mineral, yet whenever hot water glistens on its surface the formation is brilliant with color. The oranges, yellows, greens and browns are from a great number of tiny living bacteria and algae. Approximately sixty-five species of thermal algae live in the waters of Mammoth Hot Springs and reflect varying conditions of such environmental factors as temperature, acidity, sunlight and carbon dioxide concentrations. White and bright yellow thermal bacteria predomin

Opal Spring flows at the base of Capitol Hill across the road from Liberty Cap. After years of dormancy, this spring became active in 1926 and began depositing up to a foot of travertine per year. In 1947 a tennis court was removed to allow natural expansion of the terrace. Further growth threatened the historic home next to Opal. Designed by Robert C. Reamer and built in 1908, the house is an example of Prairie Style architecture. Among Reamer’s other designs are the Old Faithful Inn and the Ro

This feature marks the north end of the Mammoth Hot Springs. It was named in 1871 by the Hayden Survey party because of its marked resemblance to the caps worn by colonial patriots during the Revolutionary War. It stands today as an extinct hot spring cone. Its outer surface has been cool and dry for many years and supports a plant community much different from that found at the active hot springs. Near the top are patches of orange lichen which are the pioneers at work breaking the rock into so

Minerva Spring is centrally located within the lower terrace group and is easily accessible by trail from the various parking areas. This spring is a favorite not only because of its wide range of bright colors, but also for its ornate travertine formations. Since the 1890’s when the first records were kept on the activity of the Mammoth Hot Springs, Minerva has gone through a series of active and inactive periods. For several years in the early 1900’s it was completely dry, but by 1951 it was a

Jupiter Spring is situated just south of Minerva. It was named in the 1880’s because of its imposing and towering formation. Jupiter was a Roman god of the elements: the thunderbolt was his sign and the rainbow his messenger. If you listen quietly you may hear the hot water thundering down the terraces of this feature. The rainbow of algae covering its terraces is obvious. The entrance to the Mammoth Terrace Drive is one and one-half miles south of the Mammoth Visitor Center on the road to Norri

This viewpoint offers an excellent overview of the springs and pools of the Lower Terraces. The large blue pool ahead and to the right is Canary Spring. The pools visible to the left are the New Blue Springs complex. The names of these features suggest colors which are inconsistent with what we see today. The color of both features has changed from when they were originally named. Changes in environmental conditions may account for this: perhaps a change in water temperature. The trail to the le

Activity began at New Highland Spring in 1952. The continuous heavy flow of mineral laden water has caused a very rapid development of this beautiful terrace. Prior to that time a luxuriant growth of trees, shrubs and flowers covered this hillside. The tree skeletons being engulfed by travertine stand as monuments to the former conditions. To the right of New Highland still stands a portion of dense vegetative cover growing on a north facing slope. Most noticeable upon close inspection is the am

The bright orange of this formation is a clue to the temperature of its water. Also, the rate of flow and the rate of deposition are very slow. It could follow then that since we have no record of this spring ever being very active, this small mound could be considerably older than those that are much larger....

Just ahead of you is a short but very steep hill. At the bottom of this hill on the right is Bath Lake, named by some of the local residents in the 1880’s. Being a quiet pool, deposition of travertine is at a slow rate and the water remains highly mineralized with limestone. According to the old records Bath Lake was entirely dry in 1926 and remained that way until the 1959 earthquake. Although the name of this feature derives from the soldiers’ habit of swimming in it, we now know that this act

This long white ridge is unusual for a hot spring terrace and adds a touch of fantasy to the area. Someone has said that it resembles a string of circus elephants marching over the Mammoth Terraces. Take the time to view it from different angles to see what you think! The final section of the Upper Terrace Drive goes through a wooded area. Mule deer are frequently seen here, especially during the late afternoon and evening. Forest vegetation along this section is dense even though it a south-fac

At the bottom of the hill on the left are the ruins of Angel Terrace. Visitors during the 1920’s and 30’s saw it as a beautiful algae-tinted feature. Today it is beginning to crumble and young pioneer plants are taking root in the thin soil over its surface. Alteration and change are constantly occurring in the thermal basins and add to the mystery of this fascinating land. They bring not destruction and loss, but rather new birth and gain. Who knows what interesting ornate new features may deve

This guide was published for your use by The Yellowstone Association for Natural Science, History & Education, Inc. in cooperation with the National Park Service, U.S. Department of the Interior. The Yellowstone Association is a non-profit organization dedicated to service to the park and its visitors. Your donation will be used for this purpose. For information about other pamphlets, books, and maps pertaining to Yellowstone National Park or Association membership and educational activi