Call these folks and ask what to do...
http://www.mde.state.md.us/ContactUs/index.asp

For information about this, search google.com for the following words...
sinkholes Maryland



"Betsy" 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!