"robgraham" wrote in message
...
From Sciencedaily.com

"In order to study past environmental changes scientists typically
acquire samples from deposits laid down in bogs or lakes, within which
organic matter, which can be dated is preserved," explains Dr Carr.
"But in dryland environments such as southern Africa this isn't
possible. Fortunately it seems that hyrax urine preserves organic
matter over timescales of tens of thousands of years, which provides
remarkable insights into past environmental changes within the hyrax
habitat."

Obtaining the material is not easy and Dr Chase is an experienced rock-
climber, which allows him to reach middens that are often otherwise
inaccessible. The middens form extremely tough deposits, which have to
then be cut from the rocks with an angle grinder.

You'd want a bloody good dust mask!