| 词条 | Pulpit Rocks |
| 释义 |
| nrhp_type =nhl | image = Pulpit Rocks.jpg | caption = as painted in 1858 | location= Pike St. (Old US 22), northwest of Huntingdon, Pennsylvania | coordinates = {{coord|40|31|6.5|N|78|2|56.5|W|display=inline,title}} | locmapin = Pennsylvania#USA | area = {{convert|4.5|acre|ha}} | built = | architect= | architecture= | designated_nrhp_type= November 4, 1993[1] | added = November 4, 1993[2] | governing_body = Private | refnum=93001614 }} Pulpit Rocks is a geological formation adjacent to Pike Road (or Alexandria Pike Road, Old United States Route 22) northwest of Huntingdon in Huntingdon County, Pennsylvania. These weathered rock formations were instrumental in the determination of the stratigraphy of the Appalachian Mountains in the mid-19th century by the Pennsylvania Geological Survey. This work was influential in opening up new fields of geological research. The site was declared a National Historic Landmark in 1993.[1][3] It is partially owned by Juniata College, whose geology department uses the site for educational purposes. A plaque marks its location. Description and historyThe Pulpit Rocks are located along Warrior Ridge, a formation located between Huntingdon and Alexandria in the central Pennsylvania Appalachians. They are located on the north side of Pike Road, an old alignment of US 22 which now runs further south. The rock formations are essentially weathered pillars, about {{convert|50|ft|m}} in height, that are isolated from one another by about {{convert|10|ft|m}}, spaces wide enough for a human to pass through. At the time research on this formation was first published in 1858, the accompanying watercolor painting (pictured here) was described as an accurate rendition of their state. The rocks are formed out of what is called Oriskany sandstone, and rest upon layers of limestone. The stone was laid down about 390 million years ago, when the area was covered by an inland sea, and have been eroding slowly ever since.[4] Pennsylvania's Geological Survey was established in 1836, with its survey work conducted between 1836 and 1842. The Huntingdon area was one of the first to be surveyed, and John Frazer, one of the geologists on the survey team, realized that the geology of this area strongly suggested that conventional wisdom about its structure was incorrect. The prevailing belief at the time was that there were single layers of sandstone and conglomerate underlying the ridges. In this area, in particular around the Pulpit Rocks, it was clear that there were in fact multiple layers of sandstone, separated from one another by thick layers of other types of rock. This realizaton immediately illuminated findings of surveys in neighboring New York and Virginia as to the structure of the mountain formations in those states. The Pennsylvania Geological Survey's first major report, published in 1858, featured the watercolor pictured here, highlighting the formation's importance in furthering the understanding of Appalachian (and more broadly all mountain) geology.[4] See also
References1. ^1 {{cite web|url=http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=2171&ResourceType=Site|title=Pulpit Rocks |accessdate=2008-02-11|work=National Historic Landmark summary listing|publisher=National Park Service}} 2. ^{{NRISref|2007a}} 3. ^{{Cite journal|title=National Historic Landmark Nomination: Pulpit Rocks|url={{NHLS url|id=93001614}} |format=pdf|date=December 2, 1992 |author=John W. Bond |publisher=National Park Service}} and {{NHLS url|id=93001614|title=Accompanying 3 images, from 1840 and 1992|photos=y}} {{small|(32 KB)}} 4. ^1 {{cite web|url={{NHLS url|93001614}}|title=NHL nomination for Pulpit Rocks|publisher=National Park Service|accessdate=2017-04-13}} External links
3 : National Historic Landmarks in Pennsylvania|Geography of Huntingdon County, Pennsylvania|National Register of Historic Places in Huntingdon County, Pennsylvania |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。