Under car -- black tar stuff????

Hey guys,

Me again, the newbie.

Under the car there's this wet black tar looking stuff that's on numerous locations. What is this junk? Should I just clean it off or is this a sign of trouble?

View photos here

Here are 2 example photos:



I'm sorry if these are really retarded questions. This is my first classic car, and I'm trying to learn everything I can. I appreciate your patience.

Thanks,
Ian