The Miocene was the first epoch of the Neogene period (23-2.5 million years ago), followed by the much shorter Pliocene epoch (5-2.6 million years ago); both the Neogene and Miocene are themselves subdivisions of the Cenozoic Era (65 million years ago to the present). Climate and geography.
The dictionary meaning of the word Digress is 'to leave the main subject temporarily in speech or writing.' or simply deviate. As you say,I digress means  I am straying from the main subject right now. . Like in this sentence - 'I need to digress a bit to let the ink dry.'. Hope this helps :)
digression A diversion is an action or event that attracts your attention away from what you are doing or concentrating on. The robbers threw smoke bombs to create a diversion. The whole argument is a diversion. Synonyms: distraction, deviation, deflection, digression More Synonyms of diversion.