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.
Oh, and it should also be reasonably common. The first aspect is the least important, but it's nevertheless useful. The fossil record is famously incomplete, and though we still have much to learn about prehistoric life, we can at least, thanks to a particular type of fossil, begin to organize it.