Hello,
There are these black or tan little circular objects in the dirt in my garden (see photos). As you can see some are dark and some are light (almost cream colored).
What is this stuff? Should I be worried about it? Should I try to dig it up? Is it dangerous?
Thanks for your help!!!
Susan

They are Bird's Nest fungus. They are not harming anything but are breaking down your compost into dirt.

It appears to be a type of Birds Nest Fungi; Cyathus:
http://www.mushroomexpert.com/...
http://virtualnaturecenter.wee...
http://healthyhomegardening.co...

Like other fungi, they are usually seen in decomposing organic matter. Some mushrooms/fungi are toxic if eaten and I don't know about this variety but they should not be harmful as long as they aren't eaten.