mgg wrote:
"Frogwatch" wrote in message
...
On Jan 4, 10:27 pm, "mgg" wrote:
"Frogwatch" wrote in message

...
On Jan 4, 8:00 pm, Wayne.B wrote:

On Mon, 4 Jan 2010 14:39:09 -0800 (PST), Frogwatch
wrote:
I resolve to carry a compass even on
short trips into the woods from now on.
A pocket GPS is even better, and useful in the dinghy also.
In deep woods, GPS often has problems and does not work at all in
caves.



I have to wonder how well a compass would work in some caves as well.
Depending on the composition of the rock, it could drive a compass whacky.

Here's a thought... carry both! ;-)

--Mike

My compass has never failed me. Most caves are in limestone so
compositioin does not change the earths mag field.


Limestone.... I did not know that.

My only experience with caves is: http://www.mercercaverns.com/ which is
limestone as well. I didn't know it was the norm though. Very cool tour
there as well. I doubt it's your cup-o-tea since they built steps. ;-)

--Mike


We toured Lurray Caverns up in Hairball the paste eater's neighborhood,
this summer. Pretty Cool place. They even had a mechanical organ that
used ( limestone icicles ) stalactites, i think, instead of pipes. It's
worth a look if you are traveling in the vicinity.