Barron, H F, Gillespie, M R and Merritt, J W 2011. Geodiversity of the Cairngorms National Park. British Geological Survey Open Report, OR/10/019 A PDF of this report is available from the NORA, the NERC archive
Site no.: B14
Site name: Forest Lodge
Grid reference:
Locality: In the vicinity of Forest Lodge, Glen Tilt
GCR Status: Confirmed
GCR No.: 2068
Type: Natural section
Description: Exposures of granitic rocks and their Dalradian country rocks in the bed of the River Tilt within a section of the river between approximately 800 m upstream and 300 m downstream of Forest Lodge. The GCR volume 'Caledonian igneous rocks of Great Britain' (Stephenson et al., 1999) contains a full description of the site.
Justification: The site is of international importance on historical grounds. It was here in 1785 that James Hutton first found and documented field evidence to support his theory that granite was intruded into country rocks in a hot, fluid state, i.e. magma, and that this matter was able to flow within Earth's crust, veining, disrupting and recrystallizing pre-existing rocks. The conclusion that granite is not universally the earliest formed rock effectively ended one of the major geological controversies of the time.