Final answer:
If you find locate markings at a Gas Company excavation site, you should verify them with current utility maps for safety and avoid potential damage. The age of fossils at any geological site varies depending on the strata, and cliff faces or road cuts can provide valuable geologic information, although not as comprehensive as larger cross-sections.
Step-by-step explanation:
If you are at a proposed Gas Company excavation site and locate markings are already present, you should not ignore them. These markings indicate where existing underground utilities and infrastructure are located. Respecting these markings is essential for safety and preventing damage to these utilities.
Before starting any excavation, it's critical to verify these markings with the current utility maps and to ensure that the markings are still valid since conditions may have changed since they were made.
Regarding the geological aspect such as visiting locations for fossils, the age of the fossils found would vary greatly depending on the geological strata exposed at the particular location.
If you are marking a few locations on a map to visit for potential fossil findings, it would be important to research the geologic history of those areas to know what kind of fossils you might expect to find and from what time period they originated.
When geologists have access only to cliff faces or road cuts, they can indeed gather information about the geological history, but it may not provide a complete picture as a more extensive cross-section would.
However, these exposures can still offer valuable insights into the geological history of the area, including the types of rocks present, their formation, and the processes that exposed them.