Despite 35 years of technological refinement and better under-standing, the underlying assumptions have been strongly challenged... "Throughout the conference emphasis was placed on the fact that laboratories do not measure ages, they measure sample activities. To some thoughtful stratigraphers this amazing discovery presented a dilemma, for if the known stratified rocks have been accumulating throughout this vast span of time the average rate of deposition must have been extremely slow, yet there is very good evidence that individual beds accumulated rapidly.
It should be no surprise, then, that fully half of the dates are rejected. The connection between activity and age is made through a set of assumptions. Thus Schuchert...found that if a geologic column were built up by superposing the thickest known part of each of the geologic systems in North America, from Cambrian to the present, the composite record would be about 259,000 feet thick.
However this web site ( convinced me that they could be useful as a reference tool, especially for those who attend the lectures, and I agreed.
In contrast, areas in which sand accumulates periodically but rapidly, as in river flood plains were sand laden waters of strong floods suddenly lose velocity are very favorable for building up ripple-laminated deposits." Society of Economic Paleontologists and Mineralogists, p.107. ...there is factual evidence from both field observation and experiment that laminae composed of bed material are commonly deposited by current action within a period of seconds or minutes." V.36, No. ..not accumulate gradually but were cast instantaneously by turbidity currents each bed in its entire thickness, in a matter of hours or less." Journal of Geology, V.70, p. But blood cells in a dinosaur bone should have disappeared eons ago. These observations suggest that in their formation, high rank coals,...probably subjected to high temperature at some stage in their history.
A few (two) have charged that a small number of these quotes misrepresent the intent of the context.