Results from different techniques, often measured in rival labs, continually confirm each other.
Every few years, new geologic time scales are published, providing the latest dates for major time lines.
Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.
These skeptics do not provide scientific evidence for their views.
Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.