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Burrough Valley, California (once also called Burr Valley) is located in the Sierra Nevada foothills of eastern Fresno County, approximately thirty miles northeast of Fresno, California, at an elevation of about above sea level. The small valley covers approximately . ==Natural history== Burrough Valley’s geology is too complicated for a complete description here. It includes both igneous and sedimentary formations and a great deal of metamorphosis resulting from a history of frequent seismic activity. The area includes fragments of an ancient island arc scraped off of a subducting plate〔Subduction〕 in the Mesozoic and later affected by the much more recent tilting up of the Sierra Nevada batholith and igneous intrusions. It also contains ancient sea floor and mantle〔Mantle (geology)〕 hundreds of millions of years old. These are almost always metaphosed due to the complicated and dynamic techtonic and volcanic activity. Rocks include light colored leucogranites as well as darker gabbro and peridotite. Quartzite and feldspar are also found, mostly remobilized from hydrologic activity. California's state rock, serpentine, metamorphosed mantle, is common; but not as much as in the Gold Country north of the San Joaquin River. Serpentine is the gold bearing rock of the Gold Country, and some gold was mined in the Burrough Valley area, especially Watts Valley and Copper King Mountain. But these were not rich strikes. The climate is relatively dry with an average annual rainfall of about 20-25 inches but varying greatly within a range of less than to more than . The area is central oak woodland,〔http://www.laspilitas.com/nature-of-california/communities/central-oak-woodland〕 grassland and chaparral. The valley's trees include the valley oak, the blue oak, and the interior live oak. Along the intermittent streams are found willows, cottonwoods, and white-barked sycamores. South facing hillsides are relatively barren, with scattered patches of buck brush (ceanothus) and scrubby blue oaks and live oaks. North facing hillsides are often covered with thick manzanita, poison oak, live oak, California buckeye (aesculus californica) and buck brush. In the spring, especially after wet winters, wildflowers proliferate, including the California poppy, the Mariposa lily, many forms of lupin and brodiaea.〔 〕 Burrough Valley is habitat to many animals and birds, including black-tailed deer, mountain lion, bobcat, coyote, cottontail, gray squirrel, California ground squirrel, and many smaller rodents. Wild pigs were introduced or migrated to the area in the 1980s. Feral pigs, which escaped from early settlers, were once common in the 1900s and early 20th century. Reptiles inhabiting the area include the northern Pacific rattlesnake,〔 〕 gopher snake, two species of king snake, garter snake, northern alligator lizard, western fence lizard, skink, and whiptail lizard. The area’s amphibians include the tree frog, California newt, several species of salamander, toad, and American bull frog, which was introduced in the 19th century. The foothill yellow-legged frog〔http://www.californiaherps.com/frogs/pages/r.boylii.html〕 once was common, but is now rare. Golden eagles occasionally soar high above the valley and make their nests in the remote rocky crags on the mountain tops. Red-tailed hawks often ride afternoon thermals. There are also Cooper’s hawks, sharp-shinned hawks, merlins〔http://www.allaboutbirds.org/guide/merlin/id〕 and kestrels. Turkey vultures spend most of the year in the area but migrate south in winter. Crows are common. Other birds include meadow larks, mourning doves, starlings, scrub jays, Steller’s jays,〔http://animals.nationalgeographic.com/animals/birding/stellers-jay/〕〔 〕 blackbirds, sparrows, towhees, western bluebirds, Wilson’s warblers, western flycatchers,〔 〕 titmice, humming birds, and many other small birds. Wild turkeys, introduced in the 1960s, are common. Band-tailed pigeons enter the valley in the fall and winter to feast on acorns. The commonest bird is perhaps the acorn woodpecker, whose raucous laugh can be heard nearly every daytime moment. Several other species of woodpeckers are found, including the red-shafted flicker, Lewis's woodpecker and downy woodpecker. California valley quail are also common, with their call “chi-ca-GO! chi-chi-ca-GO!” heard frequently. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Burrough Valley」の詳細全文を読む スポンサード リンク
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