| 21. | Approximately 24-36 million years ago these areas were subjected to massive volcanic activity during the Tertiary Period.
|
| 22. | The geologic formations in this area date to the early Tertiary Period, some 30 million years ago.
|
| 23. | This is due to the diversity of its geological-tectonic structure, particularly with the new vulcanization during Tertiary Period.
|
| 24. | Finally in the later part of the Tertiary period the local climate entered a trend of increasing temperatures.
|
| 25. | The Cenozoic is sometimes divided into the Quaternary and Tertiary periods, although the latter is no longer used officially.
|
| 26. | These fossils range from the Triassic to the Tertiary periods, but are mostly restricted to the Triassic and Jurassic.
|
| 27. | After being periodically submerged during the Jurassic and Cretaceous periods, the region finally became land in the Tertiary period.
|
| 28. | The formation of the Rocky Mountains began in the Late Cretaceous Period and finished in the Early Tertiary Period.
|
| 29. | This basin was formed by a prehistoric lake ( " Uinta Lake " ) during the late Tertiary period.
|
| 30. | There are few if any rocks from the ensuing Tertiary period of the Cenozoic era in Pennsylvania's geologic record.
|
