Glen Tilt
Encyclopedia
Glen Tilt is a glen
in the extreme north of Perthshire
, Scotland
. Beginning at the confines of Aberdeenshire
, it follows a South-westerly direction excepting for the last 4 miles, when it runs due south to Blair Atholl
. It is watered throughout by the Tilt, which enters the Garry after a course of 14 miles, and receives on its right the Tarf, which forms some beautiful falls just above the confluence, and on the left the Fender, which has some fine falls also. The attempt of the 6th Duke of Atholl (1814–1864) to close the glen to the public was successfully contested by the Scottish Rights of Way Society. The massive mountain of Beinn a' Ghlò and its three Munro
s Càrn nan Gabhar (1129 m), Bràigh Coire Chruinn-bhalgain (1070 m) and Càrn Liath (975) dominate the glen's eastern lower half.
Marble of good quality is occasionally quarried in the glen, and the rock formation has long attracted the attention of geologists. One of the earliest was James Hutton
, who visited the glen in 1785 and found boulders with granite
penetrating metamorphic
schist
s in a way which indicated that the granite had been molten
at the time. This showed to him that granite formed from cooling of molten rock, contradicting the ideas of Neptunism
of that time that theorised that rocks were formed by precipitation
out of water. Hutton concluded that the granite must be younger than the schists. This was one of the findings that led him to develop his theory of Plutonism
and the concept of an immensely long geologic time scale
with "no vestige of a beginning, no prospect of an end."
Glen
A glen is a valley, typically one that is long, deep, and often glacially U-shaped; or one with a watercourse running through such a valley. Whittow defines it as a "Scottish term for a deep valley in the Highlands" that is "narrower than a strath."...
in the extreme north of Perthshire
Perthshire
Perthshire, officially the County of Perth , is a registration county in central Scotland. It extends from Strathmore in the east, to the Pass of Drumochter in the north, Rannoch Moor and Ben Lui in the west, and Aberfoyle in the south...
, Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. Beginning at the confines of Aberdeenshire
Aberdeenshire
Aberdeenshire is one of the 32 unitary council areas in Scotland and a lieutenancy area.The present day Aberdeenshire council area does not include the City of Aberdeen, now a separate council area, from which its name derives. Together, the modern council area and the city formed historic...
, it follows a South-westerly direction excepting for the last 4 miles, when it runs due south to Blair Atholl
Blair Atholl
Blair Atholl is a small town in Perthshire, Scotland, built about the confluence of the Rivers Tilt and Garry in one of the few areas of flat land in the midst of the Grampian Mountains. The Gaelic place-name Blair, from blàr, 'field, plain', refers to this location...
. It is watered throughout by the Tilt, which enters the Garry after a course of 14 miles, and receives on its right the Tarf, which forms some beautiful falls just above the confluence, and on the left the Fender, which has some fine falls also. The attempt of the 6th Duke of Atholl (1814–1864) to close the glen to the public was successfully contested by the Scottish Rights of Way Society. The massive mountain of Beinn a' Ghlò and its three Munro
Munro
A Munro is a mountain in Scotland with a height over . They are named after Sir Hugh Munro, 4th Baronet , who produced the first list of such hills, known as Munros Tables, in 1891. A Munro top is a summit over 3,000 ft which is not regarded as a separate mountain...
s Càrn nan Gabhar (1129 m), Bràigh Coire Chruinn-bhalgain (1070 m) and Càrn Liath (975) dominate the glen's eastern lower half.
Marble of good quality is occasionally quarried in the glen, and the rock formation has long attracted the attention of geologists. One of the earliest was James Hutton
James Hutton
James Hutton was a Scottish physician, geologist, naturalist, chemical manufacturer and experimental agriculturalist. He is considered the father of modern geology...
, who visited the glen in 1785 and found boulders with granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
penetrating metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...
s in a way which indicated that the granite had been molten
Mölten
Mölten is a comune in South Tyrol in the Italian region Trentino-Alto Adige/Südtirol, located about 60 km north of Trento and about 12 km northwest of Bolzano .-Geography:...
at the time. This showed to him that granite formed from cooling of molten rock, contradicting the ideas of Neptunism
Neptunism
Neptunism is a discredited and obsolete scientific theory of geology proposed by Abraham Gottlob Werner in the late 18th century that proposed rocks formed from the crystallisation of minerals in the early Earth's oceans....
of that time that theorised that rocks were formed by precipitation
Precipitation (chemistry)
Precipitation is the formation of a solid in a solution or inside anothersolid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid, the solid formed is called the precipitate, or when compacted by a centrifuge, a pellet. The liquid remaining above the solid...
out of water. Hutton concluded that the granite must be younger than the schists. This was one of the findings that led him to develop his theory of Plutonism
Plutonism
Plutonism is the geologic theory that the rocks forming the Earth were formed in fire by volcanic activity, with a continuing gradual process of weathering and erosion wearing away rocks, which were then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and...
and the concept of an immensely long geologic time scale
Geologic time scale
The geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth...
with "no vestige of a beginning, no prospect of an end."