The
Boston Mountains area is a high and deeply
dissected plateauA dissected plateau is a plateau area that has been uplifted, then severely eroded so that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or...
located in northern
ArkansasArkansas is a state located in the southern region of the United States. Its name is an Algonquin name of the Quapaw Indians. Arkansas shares a border with six states, with its eastern border largely defined by the Mississippi River. Its diverse geography ranges from the mountainous regions of the...
and eastern
OklahomaOklahoma is a state located in the South Central region of the United States of America. With an estimated 3,617,316 residents in 2007 and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
. The Oklahoma portion of the range is locally referred to as the
Cookson HillsThe Cookson Hills are in the eastern part of Oklahoma. They are an extension of the Boston Mountains of Arkansas to the east and the southwestern margin of the Ozark Plateau. They lie generally between Stilwell, Oklahoma, Sallisaw, Oklahoma and Tahlequah, Oklahoma. The area became part of the...
. The rocks of the region are essentially little disturbed, flat-lying sedimentary layers of the
PaleozoicThe Paleozoic or Palaeozoic Era is the earliest of three geologic eras of the Phanerozoic eon...
age. The highest ridges and peaks are capped by
PennsylvanianThe Pennsylvanian is in the ICS geologic timescale the youngest subperiod or upper subsystem of the Carboniferous period. It lasted from roughly to Ma . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the...
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
and
shaleShale is a fine-grained, clastic sedimentary rock composed of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable...
. The deeply eroded valleys are cut into Mississippian
limestoneLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...
s and below that layer
OrdovicianThe Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian period and is followed by the Silurian period...
dolomiteDolomite is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg
2 found in crystals....
s.
The Boston Mountains form the southwestern part of the
OzarkThe Ozarks are a physiographic, geologic, and cultural highland region of the central United States. It covers much of the south half of Missouri and an extensive portion of northwest and North central Arkansas...
plateau where they are the highest and most rugged portion of the Ozarks.
The
Boston Mountains area is a high and deeply
dissected plateauA dissected plateau is a plateau area that has been uplifted, then severely eroded so that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or...
located in northern
ArkansasArkansas is a state located in the southern region of the United States. Its name is an Algonquin name of the Quapaw Indians. Arkansas shares a border with six states, with its eastern border largely defined by the Mississippi River. Its diverse geography ranges from the mountainous regions of the...
and eastern
OklahomaOklahoma is a state located in the South Central region of the United States of America. With an estimated 3,617,316 residents in 2007 and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
. The Oklahoma portion of the range is locally referred to as the
Cookson HillsThe Cookson Hills are in the eastern part of Oklahoma. They are an extension of the Boston Mountains of Arkansas to the east and the southwestern margin of the Ozark Plateau. They lie generally between Stilwell, Oklahoma, Sallisaw, Oklahoma and Tahlequah, Oklahoma. The area became part of the...
. The rocks of the region are essentially little disturbed, flat-lying sedimentary layers of the
PaleozoicThe Paleozoic or Palaeozoic Era is the earliest of three geologic eras of the Phanerozoic eon...
age. The highest ridges and peaks are capped by
PennsylvanianThe Pennsylvanian is in the ICS geologic timescale the youngest subperiod or upper subsystem of the Carboniferous period. It lasted from roughly to Ma . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the...
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
and
shaleShale is a fine-grained, clastic sedimentary rock composed of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable...
. The deeply eroded valleys are cut into Mississippian
limestoneLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...
s and below that layer
OrdovicianThe Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian period and is followed by the Silurian period...
dolomiteDolomite is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg
2 found in crystals....
s.
The Boston Mountains form the southwestern part of the
OzarkThe Ozarks are a physiographic, geologic, and cultural highland region of the central United States. It covers much of the south half of Missouri and an extensive portion of northwest and North central Arkansas...
plateau where they are the highest and most rugged portion of the Ozarks. Summits can reach elevations of just over 2,560 feet with valleys 500 to 1,550 feet deep. Turner Ward Knob (TWK) is the highest named peak. Located in western
Newton County, ArkansasNewton County is a county located in the U.S. state of Arkansas. As of 2000, the population is 8,608. The county seat is Jasper. Newton County is Arkansas's 46th county, formed on December 14, 1842, and named for Thomas W. Newton, an Arkansas Congressman...
, its elevation is 2,463 feet. Nearby, five unnamed peaks have elevations at or slightly above 2,560 feet. Two of these highest peaks are located 2.2 miles west of TWK, one being the location of the Buffalo Lookout fire tower. The other three highest peaks are located 4–5 miles SSW of TWK along Arkansas State Highway 16.
The Boston Mountains are the source of rivers and streams that flow out from the mountains in all directions. Within a 3 mile radius of a point just west of the summits discussed above are located the sources of the
White RiverThe White River is a 722 mile long river that flows through the U.S. states of Arkansas and Missouri.-Course:The source of the White River is in the Boston Mountains of northwest Arkansas, in the Ozark-St. Francis National Forest southeast of Fayetteville...
, the
Buffalo RiverThe Buffalo River, located in northern Arkansas, was the first National River to be designated in the United States. The Buffalo River is slightly more than in length, with the lower flowing within the boundaries of an area managed by the National Park Service, where it is designated the '. The...
, the Kings River, War Eagle Creek, and Little Mulberry Creek. Other rivers and streams having their headwaters in the Boston Mountains include the
Illinois RiverThe Illinois River is a tributary of the Arkansas River, approximately 100 mi long, in the U.S. states of Arkansas and Oklahoma.It rises in the Ozark Mountains in the northwest corner of Arkansas, in Washington County southwest of Fayetteville, near the town of Hogeye...
, the
Mulberry RiverThe Mulberry River is a tributary of the Arkansas River, about 70 mi long, in northwestern Arkansas in the United States. Via the Arkansas River, it is part of the watershed of the Mississippi River...
,
Lee CreekLee Creek is a small river in Arkansas which starts near West Fork in Washington County and flows south to the Arkansas River passing through Crawford County near the Arkansas-Oklahoma state line.-External links:*...
, Frog Bayou, Big Piney Creek, Illinois Bayou, and the
Little Red RiverThe Little Red River is a river in north-central Arkansas. During the American Civil War the Battle of Whitney's Lane took place near Searcy on the banks of the Little Red....
. To the south, the
Arkansas RiverThe Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast and traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas....
valley separates the Boston Mountains from the
Ouachita MountainsThe Ouachita Mountains are a mountain range located in west central Arkansas, southeastern Oklahoma and north-east Texas. The range's subterranean roots may extend as far as central Texas, or beyond it to the current location of the Marathon Uplift...
.
In Arkansas the Boston Mountains are found in the following counties:
BooneBoone County is a county located in the U.S. state of Arkansas. As of the 2000 census, the population was 33,948. The county seat is Harrison. Boone County is Arkansas's 62nd county, formed on April 9, 1869...
,
CarrollCarroll County is a county located in the U.S. state of Arkansas. As of the 2000 census, the population was 25,357. The county has two county seats, Berryville and Eureka Springs...
,
CleburneCleburne County is a county located in the U.S. state of Arkansas. As of 2000, the population was 24,046. The county seat and most populous city in the county is Heber Springs, while the largest city by area is Greers Ferry. Cleburne County was formed on February 20, 1883, and named for...
,
ConwayConway County is a county located in the U.S. state of Arkansas. As of 2000, the population was 20,336. The county seat is Morrilton. Conway County was formed on October 20, 1825, from a portion of Pulaski County and named for Henry Wharton Conway who was the territorial delegate to the U.S....
,
CrawfordCrawford County is a county located in the U.S. state of Arkansas. It is part of the Fort Smith, Arkansas-Oklahoma Metropolitan Statistical Area. As of the 2000 census, the population was 53,247. The county seat is Van Buren. Crawford County was formed on October 18, 1820, and named for William H....
,
FranklinFranklin County is a county located in the U.S. state of Arkansas. It is part of the Fort Smith, Arkansas-Oklahoma Metropolitan Statistical Area. As of 2000, the population was 17,771. The county has two county seats, Charleston and Ozark. Franklin County was formed on December 19, 1837, and...
,
IndependenceIndependence County is a county located in the U.S. state of Arkansas. As of 2000, the population was 34,233. The county seat is Batesville. Independence County is Arkansas's ninth county, formed on October 20, 1820, from a portion of Lawrence County and named to honor the Declaration of...
,
JohnsonJohnson County is a county located in the U.S. state of Arkansas originally created from a portion of Pope County. As of 2000, the population was 22,781. The county seat is Clarksville. Johnson County is Arkansas's 30th county, formed on November 16, 1833, and named for Ben Johnson, a...
,
MadisonMadison County is a county located in the U.S. state of Arkansas. As of 2000, the population was 14,243. The county seat is Huntsville. The county was formed on September 30, 1836, and named for James Madison, President of the United States...
,
NewtonNewton County is a county located in the U.S. state of Arkansas. As of 2000, the population is 8,608. The county seat is Jasper. Newton County is Arkansas's 46th county, formed on December 14, 1842, and named for Thomas W. Newton, an Arkansas Congressman...
,
PopePope County is a county located in the U.S. state of Arkansas. As of 2000, the population was 54,469. The county seat is Russellville. The county was formed on November 2, 1829, from a portion of Crawford County and named for John Pope, the third governor of the Arkansas Territory...
,
SearcySearcy County is a county located in the U.S. state of Arkansas. As of 2000, the population was 8,261. The county seat is Marshall. The county was formed December 13, 1838, from a portion of Madison County and named for Richard Searcy, a judge in the Arkansas Territory. The city of Searcy,...
,
StoneStone County is a county located in the U.S. state of Arkansas. As of 2000, the population was 11,499. The county seat is Mountain View. The county was formed on April 21, 1873 and named for the natural stone formations in the area...
,
Van BurenVan Buren County is a county located in the U.S. state of Arkansas. As of 2000, the population is 16,192. The county seat is Clinton. The county was formed on November 11, 1833, and named for Martin Van Buren, President of the United States, who was Vice President at the time of the county's...
, and
WashingtonWashington County is a county located in the U.S. state of Arkansas. As of 2000, the population was 157,715. The county seat is Fayetteville...
.
In Oklahoma the Boston Mountains are found in these counties:
AdairAdair County is a county located in the U.S. state of Oklahoma. As of 2000, the population was 21,038. Its county seat is Stilwell. Adair County was named after the Adair family of the Cherokee tribe.-Geography:According to the U.S...
,
CherokeeCherokee County is a county located in the U.S. state of Oklahoma. As of 2000, the population was 42,521. Its county seat is Tahlequah.Cherokee County was established in 1907.-Geography:According to the U.S...
,
MuskogeeMuskogee County is a county located in the U.S. state of Oklahoma. As of 2000, the population was 69,451. Its county seat is Muskogee.-Geography:According to the U.S. Census Bureau, the county has a total area of 2,173 km²...
,
SequoyahSequoyah County is a county located in the U.S. state of Oklahoma. It is part of the Fort Smith, Arkansas-Oklahoma Metropolitan Statistical Area. As of 2000, the population was 38,972. Its county seat is Sallisaw.-History:...
, and
WagonerWagoner County is a county located in the U.S. state of Oklahoma. As of 2000, the population was 57,491. Its county seat is Wagoner.-Geography:According to the U.S. Census Bureau, the county has a total area of 1,531 km²...
.
[NAD83 geographic coordinates for TWK are N35.8631°, W093.4544°. Coordinates for the 5 unnamed highest peaks are N35.8637°, W093.4931°; N35.8607°, W093.4935°; N35.8151°, W093.4968°; N35.8126°, W093.4984°; and N35.7990°, W093.5005°]
Geology and physiography
The Boston Mountains are a
physiographic sectionThe physiographic regions of the world are a means of defining the Earth's landforms into distinct regions based upon Nevin Fenneman's classic three-tiered approach of divisions, provinces and sections, in 1916, which although they date from the mid 1910s, are still considered basically valid, and...
of the larger
Ozark PlateausThe Ozarks are a physiographic, geologic, and cultural highland region of the central United States. It covers much of the south half of Missouri and an extensive portion of northwest and North central Arkansas...
province, which in turn is part of the larger
Interior HighlandsThe U.S. Interior Highlands is a mountainous region spanning eastern Oklahoma, western and northern Arkansas, southern Missouri, and the extreme southeast corner of Kansas. The name is designated by the United States Geological Survey to refer to the combined mountainous region of the Ozarks and...
physiographic division.
The area is underlain by Pennsylvanian sandstone, shale, and siltstone, where some folding and faulting has occurred. The sandstone beds become thinner, but more shaly in the west as the mountains decline in elevation.
External links