@ Dr. Heinz Lycklama
Geologic Column Theory
nCambrian
rocks began to form ~ 600My ago
n[now
believed to be 520-530My ago]
nCambrian
period estimated to be ~ 80My
n[now
believed to be 5-10My]
nPrecambrian
rocks laid down during the prior hundreds
of millions of years
nShould
contain fossils of evolutionary ancestors of the complex vertebrates
nShould contain fossils of transitional forms linking the
complex vertebrates to common
ancestors