Mega year ago
From Conservapedia
The Mega year ago, often abbreviated as Ma of Mya [1], is a useful shorthand notation for long times that is more concise than scientific notation. The time for geological events such as the formation of a mountain is typically on the order of a few Ma.
Use
Instead of "trilobites went extinct 251 million years ago" [2], one would write "trilobites went extinct 251 Ma". The use of "Ma" avoids word repeats when writing papers.
