Legacy of cigarette butts, maybe? (Score 1)

It seems to me that black blobs like this occur where cigarette butts are likely to have been discarded. The ones I see do not visually thick or gooey enough to be gum--and they're black, black, black. Looks to me like someone dropped a drop of asphalt crack filler on the concrete or brick surface. So would there be some process that would turn a cigarette filter and/or cigarette ash and/or unburned tobacco into such a blob?