Death Valley National Monument
California


Fossils Indicate Marine Life

The Paleozoic rocks which are later than either of the groups described above consist chiefly of limestone and quartzites and contain a great abundance and variety of fossils indicative of former marine life. Their dominant color is somber gray but theri zebra-like banding makes them conspicuous from a distance. All the great systems of the paleozoic are represented. The best continuous section to be seen within the national monument is along the north side of the road between Death Valley Junction and the Furnace Creek Inn, where they form the southwest slopes of the Funeral Mountains. The beds here are successively older from east to west.

The Mesozoic is represented only by granite which cuts the paleozoic and older rocks and is overlain unconformably by the Tertiary rocks. No exposures are crossed by the main roads but large bodies may be seen at the head of Cottonwood Canyon north of Emigrant Wash and in Warm Springs and Anvil Canyons in the southern Panamint Range, where its relations are best seen.

The Tertiary rocks overlie unconformably all older rocks. They are non-marine and include much volcanic rock in different forms as well as shale, limestone, sandstone, and conglomerate. In general, they were formed in broad valleys and on mountain slopes much like the playas and adjacent slopes today, but volcanic activity at that time was abundant and diversified in comparison with its quiescence now. The Tertiary rocks are interesting for the unusual and, in places, brilliant colors. No animal remains have yet been found in them but some contain boron minerals, salt, and other minerals. The beds are widely and irregularly distributed through the Death Valley region. The largest area lies along the Furnace Creek Road, but more strikingly colored rocks of this age may be seen from the road that leads southward from Furnace Creek Inn to Bad Water.

The Quaternary or youngest rocks of the region include all the alluvial fans, the great salt deposits at the bottom of Death Valley, many dissected gravel terraces, and other dissected lake beds in Amargosa Valley near Shoshone. Bones and teeth of the elephant or mammoth have been found in a bed of volcanic ash overlying these lake beds at Shoshone. The salt deposit (Devil's Golf Course) on the floor of Death Valley represents the saline residue of an evaporated lake. Wells 1,000 feet deep drilled in the deposit have gone through alternating beds of clay and salt without reaching bedrock. Each salt and clay bed probably represents the drying up of a Quaternary lake, the uppermost representing the latest. Sets of faint terraces here and there, as at Mormon Point, may mark the shores of this lake. The Ubehebe craters in the northern part of Death Valley are cinder cones of very late Quaternary (recent) age. Some of them are probably not over a few hundred years old.


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