where they can be seen from unimproved roads. One of these relatively small granitic plutons was emplaced 67–87 Ma and spawned one of the more profitable precious metal deposits in the Death Valley area, giving rise to the town and mines of Skidoo. In the Death Valley area these solidified blobs of magma are located under much of the Owlshead Mountains and are found in the western end of the Panamint Mountains. Thrusted areas can be seen at Schwaub Peak in the southern part of the Funeral Mountains. A long period of uplift and erosion was concurrent with and followed the above events, creating a major unconformity. Sediments worn off the Death Valley region were shed both east and west and carried by wind and water; the eastern sediments ended up in Colorado and are now famous for their dinosaur fossils. No Jurassic to Eocene sedimentary formations exist in the area except for some possibly Jurassic-age volcanic rock around Butte Valley. Large parts of previously deposited formations were removed; probably by streams that washed the sediment into the Cretaceous Seaway that longitudinally divided North America to the east. Development of a plain After 150 million years of volcanism, plutonism, metamorphism, and thrust faulting had run their course, the early part of the Cenozoic era (early Tertiary, 65–30 Ma) was a time of repose; neither igneous nor sedimentary rocks of this age are known here. A relatively featureless plain was created from erosion over many millions of years. Deposition resumed some 35 Ma in the Oligocene epoch on a flood plain that developed in the area; sluggish streams migrated laterally over the surface, laying down cobbles, sand, and mud. Outcrops of the resulting conglomerates, sandstone, and mudstone of the Titus Canyon Formation can be observed in road cuts at Daylight Pass on Daylight Pass Road, which becomes State Route 374 a short distance from the pass. Several other similar formations were also laid down. Large volcanic eruptions, originating near the Nevada Test Site, covered the Death Valley area and much of Nevada in thick sequences of silica-rich ash 27 million years ago. The ash has a rhyolitic composition, which is the volcanic equivalent of the plutonic rock granite; it covered what would later become the Grapevine Mountains in of ash. This ash filled in valleys and depressions; by 20 million years ago, the region from the Death Valley area across Nevada