Ripped up carpet and found this underneath

[babychickypoo]

My husband just ripped carpet out of our daughter's room and found this black stuff under some carpet padding. Does anyone know what it is or if it is asbestos?

 

[Floorist]

Looks like old black rubber from glue-down rubberback carpet. If it is, no asbestos.

 

[rugaddict]

could be tarpaper ---no asbestos there either