During the last glacial maximum 20,000 years ago the sea level was about 130 meters below today's [1] so agriculture would be found above that. About a hundred thousand years before that sea levels were close to modern levels and the current ice age [2] started almost half a million years after the first stone industry [3] got started, so sea levels would have been much higher (200-300 meters higher than today).
[1] https://en.wikipedia.org/wiki/Past_sea_level
[2] https://en.wikipedia.org/wiki/Quaternary_glaciation
[3] https://en.wikipedia.org/wiki/Oldowan