Pinnacle Rock, , is a traprock mountain peak located southwest of

Hartford, Connecticut Hartford is the List of capitals in the United States, capital city of the U.S. state of Connecticut. The city, located in Hartford County, Connecticut, Hartford County, had a population of 121,054 as of the 2020 United States census, 2020 ce ...

, in the towns of Farmington and Plainville. It is part of the narrow, linear Metacomet Ridge that extends from

Long Island Sound Long Island Sound is a sound (geography), marine sound and tidal estuary of the Atlantic Ocean. It lies predominantly between the U.S. state of Connecticut to the north and Long Island in New York (state), New York to the south. From west to east, ...

near

New Haven, Connecticut New Haven is a city of the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound. With a population of 135,081 as determined by the 2020 United States census, 2020 U.S. census, New Haven is List ...

, north through the Connecticut River Valley of

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

to the

Vermont Vermont () is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York (state), New York to the west, and the Provinces and territories of Ca ...

border. Pinnacle Rock, popular as an outdoor recreation destination in the metropolitan Hartford area, is known for its clifftop scenic vistas, unique

microclimate A microclimate (or micro-climate) is a local set of atmosphere of Earth, atmospheric conditions that differ from those in the surrounding areas, often slightly but sometimes substantially. The term may refer to areas as small as a few square m ...

ecosystems, rare plant communities, and as a seasonal raptor migration path. Pinnacle Rock is traversed by the Metacomet Trail. Pinnacle Rock should not be confused with ''The Pinnacle'', a name used for two other peaks also on the Metacomet Ridge in Connecticut (on Talcott Mountain and Higby Mountain).

Geography

Pinnacle Rock occupies the high point of a long mountain ridge which rises steeply above the upper Quinnipiac River valley to the southwest and the Farmington River valley to the northwest. The summit is bald and offers extensive views west over the valleys and suburban Farmington, toward the Berkshire Mountains. The Metacomet Ridge continues north from Pinnacle Rock as Rattlesnake Mountain and south as Bradley Mountain. The Quinnipiac River, no more than a brook this far north, passes through the gap between Pinnacle Rock and Bradley Mountain. The northeast side of Pinnacle Rock drains into Trout Brook, then to the Park River, thence into the

Connecticut River The Connecticut River is the longest river in the New England region of the United States, flowing roughly southward for through four states. It rises 300 yards (270 m) south of the U.S. border with Quebec, Canada, and discharges into Long Isl ...

and

; the rest of the mountain supports the headwaters of the Quinnipiac River, which flows directly into Long Island Sound.

Former missile site

HA-67 was a Nike 1B defensive missile base which operated from 1956 through March 1961 on the Plainville side of the rock near Loon Lake, southeast of the summit. The base is no longer in existence, with little remaining other than a parking lot and a few buildings which have been reduced to rubble. Further southeast is a small wide) traprock quarry.

Geology and ecology

Pinnacle Rock, like much of the Metacomet Ridge, is composed of

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

, also called traprock, a

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

rock. The mountain formed near the end of the

Triassic Period The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the ...

with the

rifting In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear Fault (geology), downfaulted depression, called a graben, or more commonly ...

apart of the

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

n continent from

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

and

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

Lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

welled up from the rift and solidified into sheets of strata hundreds of feet thick. Subsequent

faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

and

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

activity tilted the strata, creating the cliffs and ridgeline of Pinnacle Rock. Hot, dry upper slopes, cool, moist ravines, and mineral-rich ledges of basalt talus produce a combination of

ecosystems on the mountain that support plant and animal species uncommon in greater Connecticut. Pinnacle Rock is also an important raptor migration path. (See Metacomet Ridge for more information on the geology and ecosystem of Pinnacle Rock).

Recreation and conservation

Pinnacle Rock is traversed by the Metacomet Trail, (maintained by the Connecticut Forest and Park Association), which extends from the

Hanging Hills The Hanging Hills of south central Connecticut, United States, are a range of mountainous trap rock ridges overlooking the city of Meriden, Connecticut, Meriden and the Quinnipiac River, Quinnipiac River Valley below. They are a subrange of the ...

Meriden, Connecticut Meriden ( ) is a city in New Haven County, Connecticut, United States, located halfway between the regional cities of New Haven, Connecticut, New Haven and Hartford, Connecticut, Hartford. The city is part of the South Central Connecticut Planni ...

, to the Massachusetts border. The Metacomet Trail on the mountain is open to

hiking A hike is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century. Long hikes as part of a religious pilgrimage have existed for a much longer time. "Hi ...

, bird watching, picnicking,

snowshoeing Snowshoes are specialized outdoor gear for walking over snow. Their large footprint spreads the user's weight out and allows them to travel largely on top of rather than through snow. Adjustable bindings attach them to appropriate winter footw ...

, and other active pursuits. The ecosystem of Pinnacle Rock is most threatened by development and quarrying. In 2000, Pinnacle Rock was included in a study by the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

for the designation of a new National Scenic Trail now tentatively called the New England National Scenic Trail, which would include the Metacomet-Monadnock Trail in Massachusetts and the Mattabesett Trail and Metacomet Trail trails in Connecticut.

References

* Farnsworth, Elizabeth J.
Metacomet-Mattabesett Trail Natural Resource Assessment.
2004. PDF wefile cited November 1, 2007. * ''Connecticut Walk Book: A Trail Guide to the Connecticut Outdoors.'' 17th Edition. The Connecticut Forest and Park Association. Rockfall, Connecticut. Undated. * Raymo, Chet and Maureen E. ''Written in Stone: A Geologic History of the Northeastern United States''. Globe Pequot, Chester, Connecticut, 1989.
U.S. Congress ''New England National Scenic Trail Designation Act.''
* Google Earth sat. images 41° 41' 59"N, 72° 49' 58"W. Cited December 19, 2007.

Cited December 19, 2007.

External links

Connecticut Forest and Park Association

NPS brochure for National Scenic Trail proposal.

{{Mountains of Connecticut Farmington, Connecticut Metacomet Ridge Tourist attractions in Hartford County, Connecticut Mountains of Connecticut Landforms of Hartford County, Connecticut Raptor migration sites