Stratha'an

The geology of the area is much influenced by the Caledonian mountain building era that began during the Ordovician period nearly 500 million years ago.

[5] The majority of the rocks within the Cairngorms National Park belong to the Dalradian Supergroup, a thick sequence of sands, muds and limestones that were deposited between about 800 and 600 million years ago on the margins of the former continent of Laurentia.

[12] An outlier of Devonian Lower Old Red Sandstone occurs around the Tomintoul area[14][15] and there is a small outcrop of limestone at Inchrory in Glen Avon.

The Cairngorm landscape displays a wide range of features associated with glaciation and periglaciation including corries and glacial troughs, moraines, kames, eskers and meltwater channels.

The source of the River Avon is conventionally said to be Loch A'an situated between the mountains of Cairn Gorm and Ben Macdui.

[22] The river thus begins its journey in the heart of the Cairngorm Mountains which are never wholly free from snow; the forests cannot extend themslves to a great height on their sides nor a tree rear its head within the region of the cold; even pasturage itself fails, and their rocky summits are covered with a downy coat of yellow sapless moss.

Six individuals, including five fifteen-year-old Edinburgh school students died of exposure when their group became stranded in the open for two nights in a blizzard.

[29][30][31] On the lower slopes of Càrn Etchachan near the rivulet of Garbh Uisge Mhor a titanic block of granite called the Shelter Stone rests on some smaller boulders.

[38] The Cairngorms have diverse bryophyte habitats and important species include Andreaea frigida or icy rock moss, which is found on the margins of the loch and in the burns that feed it.

[39] Significant examples of the semi-precious gemstone cairngorm have been found near the loch as well as blue topaz, and rare minerals appear in the granite bedrock such as chrysoberyl and columbite.

The river is joined by numerous small tributaries as it wends its way eastwards through the Forest of Glenavon to the north of Beinn a' Bhùird and Ben Avon.

[22] The area is devoid of permanent habitation and the first stand of trees is encountered at Inchrory, a shooting lodge some 14 km (8.7 mi) west of the fords.

The farm is overlooked by the Queens Cairn viewpoint and is served by a metalled road which crosses the river and continues in a northeasterly direction to the village of Tomintoul, the largest settlement in the strath.

[55] However, the mapping that accompanied military engineering works in the time of the Rough Wooing of the 1540s and Cromwell's Protectorate of the 1650s had little requirement for more detailed cartography in areas outside their immediate interest[56] such as Strath A'an.

[57] The resulting map of the Highlands shows a much more accurate rendition of the course of Strath Aa'n and the nature of the surrounding hills but there is otherwise little additional detail.

[63] The lower strath has all of the above plus a mixture of woodland and lowland creatures including red squirrels,[64] rabbits, pine martens, wild cats and Daubenton's bats.

[67] Action to prevent the spread of grey squirrels into the National Park and beyond has been successful with 2016 records in the northeast confined to a few small areas close to Aberdeen.

There are 18 species of raptor found in the moors and forests of the National Park[74] and (for example) dippers and grey wagtails can be seen by the river banks in the lower reaches.

[79] The Avon supports some of the highest altitude salmon in Scotland with juvenile fish being found at heights greater than 600 m (2,000 ft) above sea level.

A barbed bone point from the Mesolithic period has been recovered from a peat moss in Glen Avon suggesting the presence of a hunting party in this area at this time.

[16] The remains of an early Bronze Age Clava-type cairn measuring about 14 m (46 ft) in diameter are situated at Marionburgh just west of the River Avon at Ballindalloch.

[90] In the late eighteenth century the "exterior of the building and the artificial embellishment of the natural beauties, bespeak it the residence of opulence united with the most correct taste".

[91] The author of this section of the Old Statistical Account added that "by the history of Scotland in all ages, it is certain that there has been no period in which the people, high or low, of every rank, led their lives in more secure or more comfortable circumstances.

"[92] In the eighteenth century access to the English markets, gave a considerable momentum to the export of black cattle from northern Scotland.

At this time a cattle droving route existed through Strathspey, up Strath A'an and then on to Corgarff in Strathdon and Ballater on Deeside or through the Lairig an Laoigh to Braemar.

The duke's motivation for his efforts was the hope that a permanent settlement would minimise cattle theft and illegal distilling of spirits in the area.

[93] The oldest "Bridge of Avon" is situated just north of Tomintoul and once carried the Coupar Angus to Fort George military road over the river.

The station building was used as a hostel for walkers and cyclists navigating the Speyside Way that runs along the line of the dismantled railway but is now a private house.

[104] However, the remoteness of the upper Glen Aa'n is such that the direct impact of tourism here is largely limited to shooting on estates such as Inchrory, hillwalking and rock-climbing.

Similarly, the recommended approach to Beinn a' Bhùird is from Deeside with only Ben Avon being close enough to Tomintoul to offer a short route from that direction.