Potassium is a very light metal (the second least dense metal after lithium) and would float on water if it were not so reactive. Plants use it, for example, to make proteins, hence the greatest demand for potassium compounds is in fertilizers.Potassium hydroxide is a strong alkali and an important industrial chemical.Seawater also contains several isotopes of strontium, two of which researchers use for dating shells: strontium-86 and strontium-87.
It was found that certain fossils, now referred to as index fossils, were restricted to a narrow zone of strata.
Then the paleontologists use the geologists' dates as evidence for the age of the fossils! The relative order of the strata was first determined by the principles of stratification. Beagle, a very strong Bible believer, made it a point to have a copy of Lyell's book for the ship's library.
(The principle of superposition was recognized as early as 1669 by Steno.) Reverend Benjamin Richardson and Reverend Joseph Townsend were a couple of early geologists involved in this work. Obviously, even Lyell was not pushing evolution at the time.
It's just one of the tricks that have been used to make the work a little more precise. I believe he has confused the use of index fossils with evolution.
One creationist editor, who is more mellow than his unfortunate statement suggests, phrased the argument thus: Unfortunately the geologists date the rocks as the paleontologists tell them to. That passage might have come out of one of Henry Morris' books, except that Morris usually avoids crude slander. Hovind is not aware of the fact that by 1815 the broad outlines of the geologic column from Paleozoic times onward had been worked out by people who were mostly geologists.