What makes an explanation scientific?
The bedrock under Iowa is primarily limestone. In what setting does limestone form and where is one place on the planet that limestone is forming today? What can we infer about Iowa's geologic history from the presence of these limestones?
Obviously no one has invented a time machine that would Earth scientists to travel back in time and directly observe what happened millions of years ago. Given that fact, how are scientists able to know what happened way back then?