The sentence you provided is mostly grammatically correct but could be slightly clarified. The phrase "layered into the ground/grave" is somewhat unusual. A more common phrasing would be "lowered into the ground" or "placed into the grave."
Here’s a breakdown of the meaning: The sentence expresses that the speaker was present during a burial when the casket was placed into the earth.
Possible rephrasing options include:
1. "I was there when


