¿ìè¶ÌÊÓƵ

Ìý

I found a grey stone with an image of a white bird (above) on a beach in north Donegal, Ireland. How would this structure have been formed? How did the white rock get into the grey rock?

Martin O’Connor
Portglenone, County Antrim, UK

We pay £25 for every answer published in ¿ìè¶ÌÊÓƵ. To answer this question – or ask a new one – email lastword@newscientist.com.

Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

¿ìè¶ÌÊÓƵ retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.

You can also submit answers by post to: The Last Word, ¿ìè¶ÌÊÓƵ, 25 Bedford Street, London WC2E 9ES.

Terms and conditions apply.