Could we detect an ancient industrial civilization in the geological record?
(PHYSorg.com Space & Earth)

As a species, we humans tend to take it for granted that we are the only ones that live in sedentary communities, use tools, and alter our landscape to meet our needs. It is also a foregone conclusion that in the history of planet Earth, humans are the only species to develop machinery, automation, electricity, and mass communications - the hallmarks of industrial civilization.