Letter | Published:

Gibbsite in Altered Granitic Rock in North Wales

Nature volume 204, pages 673674 (14 November 1964) | Download Citation



MY attention was directed by the Nature Conservancy's chief warden for Snowdonia, Mr. Evan Roberts, to an unusual form of rock weathering on the ridge of Y Llymllwyd, which projects into Nant Ffrancon between Cwm Cywion and Cwm Coch. These are two well-developed late-glacial corries. The rock in question is exposed over an area of about 100 sq. m. in a col on the crest of the ridge at approximately 750 m (2,450 ft.), O.D., grid reference SH 631609.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    , Quart. J. Geol. Soc., 86, 191 (1930).

  2. 2.

    , in The X-Ray Identification and Crystal Structure of Clay Minerals, edit. by Brown, G. (Min. Soc., London, 1961).

  3. 3.

    , in The Differential Thermal Investigation of Clays, edit. by Mackenzie, R. C. (Min. Soc., London, 1957).

  4. 4.

    , Composition and Origin of the Antrim Laterites and Bauxites (Geol. Surv., Belfast, 1952).

  5. 5.

    , The Ayrshire Bauxitic Clay (Geol. Surv., London, 1922).

  6. 6.

    , and , Min. Mag., 29, 1 (1950).

Download references

Author information


  1. The Nature Conservancy, Penrhos Road, Bangor, Caernarvonshire.



  1. Search for DAVID F. BALL in:

About this article

Publication history





By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.