It is undoubtedly compost! The gardeners in my area use Bailey's compost from Snohomish which is nice and dark and good sX#%. It too grows a magnificent crop of weeds when seeds happen to land on it. If you have birds, you will have seeds and eventually weeds or other wanted or unwanted plants :-) I'm not sure it's possible to garden without some weeds!
Happy gardening

Put a coarse mulch like wood chips on to avoid encouraging weeds.

Here is a link that might be useful: Bark Mulch

Asphalt? It's quite scrumptious and mulch looking before it gets flattened out. It's even steaming from milllions of years of composting underground

Thank You all for your input.

This year at my Aunt's garden, we ordered in a couple loads of composted bark mulch. It wasn't black, but a very dark brown like coffee grounds. My Aunt had never mulched before and was amazed at how the uniformity brought the whole garden together.

You should be able to find suppliers in the Yellow Pages. Make sure you ask how old the mulch is. And that it is fine not coarse.

Fine mulch is also apt to form a crust.

Red-i-topsoil in Redmond sells - or at least used to sell - a black compost that they called on organically inert mulch (it wasn't, natch). It was 100-year-old composted sawdust. I think most of the topsoil places sell something black like that. It also looks darker when you first put it down, and if someone is about to be on a garden tour, no doubt s/he does a bit of top dressing!

I didn't like my choice of fine versus coarse when I wrote it. I meant that it should be uniform shreds and not chunky. Wood chips are fine for a forest path, but not a garden bed.

Possibly resulting in soil under path being in better condition than beds.