Table 24.2 shows, in color, the range in the rock record of six different fossils of the Paleozoic era. Along the top of the chart is a letter for each period of the era (C for Cambrian, P for Pennsylvanian, PR for Permian, and so on).
(a) What is the range of geologic periods for the crinoid Platycrinites?
(b) To what period does rock belong that contains the brachiopod Zygospira and the trilobite Phacops?
(c) List the fossils shown that might be found in rock of the Pennsylvanian period.
(d) Considering only the time range, indicate which of the fossils would be the best index fossil.
