Along the highest portion of the range, from Pikes Peak to Rocky Mountain National Park, the Paleozoic and Mesozoic sediments formerly draped over the top of the range have long since been washed away, leaving only the gneiss, granite, and schist of the mountain core. The almost flat tops of Longs Peak, Mt. Evans, and Pikes Peak, and the rolling upland traversed by Trail Ridge Road in Rocky Mountain National Park are thought to be remnants of the 600-million-year-old erosion surface that once existed at the top of the Precambrian rocks, and that still exists below the sedimentary rocks of the Plains Province. This surface, formed near sea level, has been raised 12,000 to 14,000 feet within the Mountain Province. Throughout most of its length, the Front Range displays some of the most striking high-altitude scenery in the world. Particularly accessible areas, well worthy of visits, are Rocky Mountain National Park, Berthoud and Loveland Passes, Mt. Evans, and Pikes Peak. In these areas the Precambrian rocks can be seen and studied, and the effects of glaciation observed. The granite, gneiss, and schist of the mountain core are shattered and broken into blocks of various sizes. The breaks between the blocks are called _joints_ if there is no apparent displacement between adjacent blocks, and _faults_ where there is obvious displacement. The joints frequently appear in parallel arrays or sets; there may be two or more intersecting sets, giving a cross-hatched appearance to large exposures. [Illustration: East-west profile across Rocky Mountain National Park, through Grand Lake and Longs Peak, showing the inferred position of the original surface of the anticlinal uplift of the Front Range. This diagram is generalized, and faults are not shown. (USGS Bull. 730a)] Restoration of surface which emerged from Cretaceous sea Restoration of Dakota sandstone MIDDLE PARK _Grand Lake_ Longs Peak Foothills GREAT PLAINS Sedimentary rocks Granite and schist Sedimentary rock of plains _South Platte R._ [Illustration: Big Thompson Canyon, west of Loveland on U.S. highway 34, is carved in almost vertical layers of Precambrian metamorphic rocks. Gently dipping Late Paleozoic and Mesozoic sedimentary rocks of the Fountain, Lyons, Lykins, and Morrison Formations can be seen in the distance, capped by the Cretaceous Dakota Sandstone. (Floyd Walters photo)] The Precambrian rocks vary from place to place. Several irregular masses of granite, called _batholiths_, make up portions of the range. Batholiths are large intrusions of molten rock that cooled slowly at great depth. The minerals in them form distinct crystals, often quite large. The Pikes Peak Granite and the Boulder Creek Granite are examples. Highly contorted and banded gneiss and schist are well exposed elsewhere, particularly in the Idaho Springs-Central City-Black Hawk region.