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.
Definition: While every fossil tells us something about the age of the rock it's found in, index fossils are the ones that tell us the most. Index fossils (also called key fossils or type fossils) are those that are used to define periods of geologic time.