1957-1961 Local interests dredged a channel across Padre Island and constructed two tetrapod jetties at the entrance to the Gulf of Mexico. The north and south jetties were 1,600 and 800 ft long, respectively, and spaced 1,000 ft apart.
The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this compresses the most recent eon. Therefore, the second scale shows the most recent eon with an expanded scale. The second scale compresses the most recent era, so the most recent era is expanded in the third scale.
The Cenozoic era is the geological time scale is divided into b â¦ oth periods and epoch. What is the geologic time scale that represents the longest time span? The geologic time scale that represents the longest time span is the eon. It is a unit of time that is equal to a billion years.