thanks. This is a very helpful reply. And thanks to the others as well.

Last night we had another 4" of rain! The hole isn't deeper, but along one
side it seems to be slightly undercut.

What if I poured a bucket of water in and watched it drain? Or filled it up
with water from the hose? Would that be telling me anything significant?

"evolutionman 2004" wrote in message
k.net...
Sinkholes are formed when the underlying soil dissolves away due to
excessive water in the area.
The underlying soil is being acted on by water leaching into the area from
a
direct source (underground pipe is broken) or an indirect source (runoff
from an uphill source). You mentioned that you've had lots of rain over
the
past 2 years & it's near a fence post. If your back-fill soil wasn't
packed
well when the post was installed, then over time, the soil around the post
(I'm assuming there's a concrete base around the post) could be slowly
dissolving away. Enlarge the area until you excavate to more solid soil,
back-fill with a clay-based soil (no gravel or organic top soil), pack
well
every 6 inches of fill, and keep working the clay-based soil into the hole
untill filled.

If you should, upon excavation of the area, notice that the water has
undermined a considerably larger area than a few feet, and that the soil
consistency is becoming sandy or crumbly, then I'd call in an company to
help with the matter. They could then determine the extent of the damage
and advise you further. Good luck!!!
"Betsy" -0 wrote in message
...
While pulling weeds today my foot fell into a hole. I jumped back and
poked
around it finding it "hollow" underneath. I got the shovel and started
digging, and found a void about 2 feet wide and 1 foot deep. There is
no
evidence of animal life in it, nor is there any debris.

1. How worried should I be? It is near the pillar supporting the post,
about 3 feet away, and about 10 feet from the foundation.

2. Should I leave it open and "watch" it or should I panic and call an
engineer or geologist or something?

The house is over 100 years old. There is no apparent drain pipe in
that
area, although I'm told the previous owner put some kind of exterior
French
drain around the house at some point. This is Baltimore, theoretically
clay
soil, although the soil in the hole is soft and sandy. It has been VERY
rainy for the last 2 years.

EGADS! PANIC! HELP!