Haycock Mountain
Encyclopedia
Haycock Mountain is a locally prominent hill with the highest summit in Bucks County
. It rises above Nockamixon State Park, in the Delaware River
drainage of southeastern Pennsylvania
. Early settlers named it simply for its "resemblance to a cock of hay."
Haycock is covered with numerous triassic diabase
boulders, and is a bouldering
destination with many established routes ranging from V0 to V10+.
Since it lies within State Game Land
Number 157, Haycock is used seasonally for hunting.
and argillite
within the Newark Basin
. As the magma cooled it became a large mass of erosion resistant diabase
below the surface. Millions of years of weathering then stripped away overlying layers of shale and argillite to expose the durable diabase to the surface, creating Haycock mountain as it appears today.
In addition to diabase, Haycock Mountain features a large area underlain by hornfels
, or local sedimentary rock that has been baked by the heat of the magma intrusion. The baked rock is most prominent within a few hundred feet of the intrusion, appearing as a dark gray hornfels. However, the magma's heat was extensive enough to produce maroon hornfels nearly a mile away.
Bucks County, Pennsylvania
- Industry and commerce :The boroughs of Bristol and Morrisville were prominent industrial centers along the Northeast Corridor during World War II. Suburban development accelerated in Lower Bucks in the 1950s with the opening of Levittown, Pennsylvania, the second such "Levittown" designed by...
. It rises above Nockamixon State Park, in the Delaware River
Delaware River
The Delaware River is a major river on the Atlantic coast of the United States.A Dutch expedition led by Henry Hudson in 1609 first mapped the river. The river was christened the South River in the New Netherland colony that followed, in contrast to the North River, as the Hudson River was then...
drainage of southeastern Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
. Early settlers named it simply for its "resemblance to a cock of hay."
Haycock is covered with numerous triassic diabase
Diabase
Diabase or dolerite is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. In North American usage, the term diabase refers to the fresh rock, whilst elsewhere the term dolerite is used for the fresh rock and diabase refers to altered material...
boulders, and is a bouldering
Bouldering
Bouldering is a style of rock climbing undertaken without a rope and normally limited to very short climbs over a crash pad so that a fall will not result in serious injury. It is typically practiced on large natural boulders or artificial boulders in gyms and outdoor urban areas...
destination with many established routes ranging from V0 to V10+.
Since it lies within State Game Land
Pennsylvania State Game Lands
The Pennsylvania State Game Lands are lands managed by the Pennsylvania Game Commission for hunting, trapping, and fishing. These lands, often not usable for farming or development, are donated to the PGC or purchased by the PGC with hunting license monies.The Pennsylvania Game Commission runs a...
Number 157, Haycock is used seasonally for hunting.
Geology
Haycock Mountain was formed 200 million years ago by an intrusion of magma into local shaleShale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
and argillite
Argillite
An argillite is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are basically lithified muds and oozes. They contain variable amounts of silt-sized particles. The argillites grade into shale when the fissile layering typical of shale is...
within the Newark Basin
Newark Basin
The Newark Basin is a sediment-filled rift basin located mainly in northern New Jersey but also stretching into south-eastern Pennsylvania and southern New York. It is part of the system of Eastern North America Rift Basins.-Geology:...
. As the magma cooled it became a large mass of erosion resistant diabase
Diabase
Diabase or dolerite is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. In North American usage, the term diabase refers to the fresh rock, whilst elsewhere the term dolerite is used for the fresh rock and diabase refers to altered material...
below the surface. Millions of years of weathering then stripped away overlying layers of shale and argillite to expose the durable diabase to the surface, creating Haycock mountain as it appears today.
In addition to diabase, Haycock Mountain features a large area underlain by hornfels
Hornfels
Hornfels is the group designation for a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and have been rendered...
, or local sedimentary rock that has been baked by the heat of the magma intrusion. The baked rock is most prominent within a few hundred feet of the intrusion, appearing as a dark gray hornfels. However, the magma's heat was extensive enough to produce maroon hornfels nearly a mile away.