Modern fossil dating techniques
This problem period may be even larger because: (1) some dating authorities believe that the effective range for K-Ar doesn't begin until about 400,000 ya, and (2) many of the older fossils are found at sites that lack the volcanic rocks necessary for K-Ar dating and hence cannot be dated by this method at all.
Although young-earth creationists challenge the legitimacy of all of the dates obtained by the long-term radiometric methods, even evolutionists are beginning to admit that this dating gap presents a problem for them.
Popular presentations of human evolution show a rather smooth transition of fossils leading to modern humans.
Evolution places severe demands upon fossils used to support it.
A fossil in an evolutionary sequence must have both the proper morphology (shape) to fit that sequence and an appropriate date to justify its position in that sequence.