Oh Say, How Far Can You See….
Purpose: This EarthCache is published by the Connecticut
Geological and Natural History Survey of the Department of
Environmental Protection. It is one in a series of EarthCache sites
designed to promote an understanding of the geological and
biological wealth of the State of Connecticut.
Supplies: You will need a copy of this login to answer
the questions once on site and be able to take a few photos on
site. Spoilers may be included in the descriptions or links.
Directions: From I-91 North or South: take Exit 35B,
which is the Bloomfield Route 218 exit. This road is also known as
Cottage Grove Road. Follow Cottage Grove Road heading west until
you hit Route 185. Follow Route 185 heading for Simsbury. At the
top of the hill, the entrance to Talcott Mountain State
Park/Heublein Tower will be on your left. From I-84 East or West:
take the Route 44 Exit. Follow Route 44 heading west until you hit
the junction of Routes 10 and 202 in the town of Avon. Follow Route
10 north until you hit Route 185 in Simsbury. Follow Route 185
heading for Bloomfield. At the top of the hill, Talcott Mountain
State Park/Heublein Tower is on your right.
Quick Description: Heublein Tower sits atop a trap-rock
ridge with an elevation of almost 1000 ft. above sea level. As such
it is almost 800 feet higher than the Farmington River Valley to
its west and 900 feet higher than downtown Hartford to the
east-southeast. From the tower one can see the Holyoke
Mountains,
about 30 miles to the north and the
Sleeping Giant, 30 miles to the south. Possibly on a clear day,
Long Island Sound, about 35 miles distant, can be seen to the
south. The view encompasses a large portion of the central lowlands
of Connecticut and the Mesozoic Hartford Basin.
N 4150.382 W 7247.554
Long Description: Heublein Tower can be found high in the
450 acre Talcott Mountain State Park system. Gilbert Heublein built
this tower as his summer home in 1914. After his death, the
property passed through several owners, before becoming a state
park in 1966. The above waymark location is in a roadside parking
area adjacent to the trailhead that will take you to Talcott
Mountain and eventually to the last waymark at the end of this
EarthCache at top of the trail.
Talcott Mountain is one part of the trap-rock ridge system in
central Connecticut. In this part of Connecticut it is called the
Metacomet Ridge. The ridge is formed by basalt (an igneous rock)
that resisted the grinding erosion of the ice age glaciers and was
left standing high above those areas underlain by more easily
erodable sedimentary rocks. Most of the various mountains in
central Connecticut and central Massachusetts are underlain by
basalt.
Basalt in Connecticut was formed about 200 million years ago
when lava poured from fissures and flowed across the land. Since
the time of eruption, the layers of lava and the sedimentary rocks
have been tilted down toward the east and eroded. The cliff on the
west side of the ridge is just the eroded edge of the down-tilted
layer of lava. The gentler eastward slope of the ridge is the
down-tilted top of the lava layer.
Magma (molten rock that is termed lava when it erupts on the
ground) is forced out of the earth by expanding bubbles of gas
(carbon dioxide and sulfur gasses are most common). Most of the gas
escapes as soon as the magma reaches the surface. As the lava flows
across the ground, some gas continues to come out of solution (much
the same way that carbon dioxide bubbles come out of solution when
you pour soda, or any carbonated beverage, into a glass). The gas
bubbles naturally floated upward through the basalt lava and
although most escaped to the atmosphere, a few got caught when the
lava cooled sufficiently to harden. 
Gas bubbles frozen in the lava are
called vesicles unless minerals have filled them, in which
case they are called amygdales. If you have a sharp eye you
can find several locations along the trail where vesicles may
be seen. Notice that they are most common at the top of the
tilted lava flow.
Activity 1. Take a picture of vesicles and send it in
with your Cache verification. What is the diameter of the
vesicles?
At the top of the trail is an open area that some use as a
taking-off spot for hang-gliding, N 41 50.102 W 72 47.883. It is a
great view location for the Farmington River Valley.
DANGER!! Care must be taken to keep a safe distance from the
cliff edge. Every year people are seriously injured because of bad
judgments along the edge of the cliff.
The Farmington River flows southeastward through a relatively
deep and narrow valley until it encounters the Metacomet Ridge in
the town of Farmington. There is makes an abrupt bend toward the
north. The view you see is of the north-flowing reach of the
Farmington River. It is unusual for a river in Connecticut to flow
northward. The river eventually breaches the ridge through
Tariffville Gorge and then flows east and southeast to join the
Connecticut River in Windsor. If you look carefully you can see the
flood plain of the Farmington River (most of which is cultivated)
and several abandoned channels in which the river used to flow. One
of the abandoned channels is a classic oxbow. The valley is
underlain by sedimentary rock (brownstones). Metamorphic rocks
underlie the hills that rise along a fairly defined line to the
west. They stand high because metamorphic rocks are more difficult
to erode than the relatively “soft” sedimentary brownstones. In
this part of Connecticut the boundary between the two different
rock types is a fault along which earthquakes regularly occurred
millions of years ago. The fault is, of course, inactive today.
At the top of the ridge follow the trail southward toward the
next waymark. In several hundred feet the trail divides. Take the
left (downhill) branch. 
You will pass a vernal pool, N 41 50.005
W 72 47.861, important to the amphibian ecology of the area, and
eventually come to a high outcrop of columnar-jointed basalt with a
short talus-slope at its base, N 41 49.707 W 72 47.884. Joint is
the geologic jargon for fracture. Columnar joints refer to the way
near vertical fractures intersect such that the rock breaks away
from the outcrop in long polygonal prisms or columns. These joints
formed after the lava solidified. Immediately after solidification
the basalt was still hot. As it cooled it shrank and as it shrank a
series of fractures formed downward from the top of the lava flow
and upward from the base of the lava flow. Blocks of the basalt
that crack and falloff the cliff accumulate at the base into a
growing pile referred to as talus (skree and slide-rock are other
terms used to describe the pile). Notice that it form
a slope of approximately 40 degrees,
which is typical for accumulations of coarse blocks of rock.
DANGER!! Do not climb the slope. Loose rocks can cause
injury to you or to others below you. Talus slopes may be
found at the base of most cliffs. In many places in
Connecticut they are covered by soil and the rock fragments
that compose them cannot be seen easily.
Continue on the trail to the last waymark, N 41 49.552 W 72
47.914, which will take you to the tower. It is called the Heublein
(pronounced “high-bline”) Tower. The top of the tower provides one
of the best vistas in the state. The tower is open seasonally
(May-October) and requires a donation for entrance. But the view
from the tower observation deck is well worth it. One can follow
the Metacomet Ridge both northward and southward. To the south one
can, on a clear day, see Avon Mountain, with the closest antennas,
Ragged Mountain, antennas farther away and more to the west,
Meriden Mountain, behind the antennas of Avon Mountain, and, if you
look carefully, beyond Meriden Mountain and Ragged Mountain, you
can make out the head of the Sleeping Giant just to the left of the
Ragged Mountain antennas. All the mountains are underlain by
trap-rock.
Looking north you can pick out the prominent peak of Mount Tom
and the peaks of the Holyoke Range to the east of Mt. Tom. Notice
also, to the north, that the Metacomet Ridge is not continuous, but
rather is broken by several valleys that displace the cliffs
eastward or westward. The valleys follow fault lines where the rock
is broken and easily eroded.
To the east is the Connecticut River Valley and the City of
Hartford and beyond the hills of the Eastern Highlands east of
Manchester, about 15 miles away, that are underlain by metamorphic
rocks. To the west is the Farmington River Valley.
The hills in the distance toward the west-northwest are just
west of Barkhamsted Reservoir, approximately 10-15 miles away. The
views may not be as far-reaching as some you get out west, but for
eastern standards, they are spectacular.
Activity 2. If the area that you can see is thought of as a
rectangle that has a long side measured by how far to the north
plus how far to the south you can see and a short side measured by
how far east plus how far west you can see, what is the area that
this magnificent view encompasses?
How do people log this EarthCache? Answer the two
activity questions and send a picture of you at the last waymark
(Hint: A particular section of the Tower will be behind you in the
photo)
More information about Heublein Tower at Talcott Mountain State
Park can be found at www.friendsofheubleintower.org
Difficulty: 1 star
Terrain: 3 stars. This has a steady strenuous uphill hike
for the first half-mile, but once on top of the ridge the hiking is
quite easy.
EarthCache category: Geologic and geographic
overview.