Accessibility Even if plenty of water is provided, there may be other limits to its use, such as the time taken for people to travel and queue to collect it. If it takes more than 30 minutes to collect water, the amount they will collect will reduce (see Figure 9.4).
. See also Geologic(al) time scale (below). Geologic(al) time scale: a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth.
The Four Geologic Eras. Geology is a complex and difficult subject, especially for the novice. I recommend that beginners first concentrate on the four major divisions of geologic history: the Geologic Eras.he Precambrian Era (4.6 billion years ago to 600 million years ago) encompasses the great majority of Earth's geologic history, stretching from the formation of our planet to the appearance of shelled marine life.