The rocks in the ridge in front of you are a record of dramatic changes in the climate and the environment of this region over time. All of the rock layers at this locality were deposited during the Mesozoic Era, (66 to 245 million years ago).
Dinosaurs, reptiles, amphibians and primitive plants dominated the land during this period.
Mammals and flowering plants began to appear at the end of this era.
The red rocks you see at the base of the ridge is the Chugwater Formation and is the most notable feature of the area. The brick-red color is caused by oxidation of iron and minerals in the rock. You may also notice streaks and spots of reduced iron creating a light bluish-gray shade. The chugwater consists mainly of siltstone or very fine-grained sandstone that is quite hard and does not break easily.
The Morrison formation is also one of the major formations visible at this location. The Morrison Formation is probably the most studied and is a distinctive sequence of late Jurassic sedimentary rock found in the western United States which has been a great source of Dinosaur fossils. It is composed of mudstone, siltstone, sandstone and limestone and the coloring is light grey, greenish grey or red.
The Pryor conglomerate forms the top of the ridge (base of the Cloverly Formation). This coarse grained rock resulted from the sand and gravel left behind by eastward flowing streams that drained rising mountains in the area of present day western Montana.
It is permissible to hike in the area of this earthcache. You may find various fossils and maybe even some CHERT. Chert is found mainly in the limestone formations. In this area it will mostly be flint but some other types of chert are Jasper, Agate, Onyx and Opal.
Please leave the fossils and any other items as found so others can enjoy them.
To log a find on this earthcache please e-mail us answers to the following questions.
1: In the Sundance Formation what are the three most common fossils found?
2: The Morrison Formation records a retreat of what and a return to what?
Each cacher is required to send the required information and not rely on another cacher to provide it. Failure to follow this procedure will result in a deleted log. Answers must be sent before logging or at the same time.
If you want to post pictures of the area we would appreciate it as this is one of our favorite areas to spend the summer.