Complex sentence: He further hypothesized that this would mean there would be oil there now-a safe bet, since the Norman Wells discovery had been made in the early 1920s, and oil seeps had been reported along the river for centuries.
Split into simpler sentences: He further hypothesized that this would mean there would be oil there now. There has been speculation that his hypothesis was not a stretch given the fact that the Norman Wells had been discovered in the early 1920s and oil seeps had been reported along the river for centuries.