Units of Measurement Conversion between metric and English units. 1 meter (m) = 39.4 inches = 1.09 yards; 1 yard = 0.92 m 1 centimeter (cm) = 0.39 inches; 1 inch = 2.54 cm 1 millimeter (mm) = 0.039 inch = 39/1,000 inch; 1 inch = 25.4 mm 1 micrometer or micron (um) = 0.000039 inch = 39/1,000,000 inch; 1/1000 inch = 25.4 um
The most important characteristics to consider when identifying Index Fossils: ABUNDANCE: To best allow paleontologists to correlate rocks with other rocks found at locations far apart, it's important that the index fossil be very widely distributed across a vast geographical region.
The ideal index fossils are those that are abundant, easy to identify, short-lived, widely distributed, and occur in many types of rocks. Abundance is important because fossils must be easy to find in the rock layer. Identifying the fossils is simpler if their shapes and features are distinctive.