Complex sentence: The surrounding valley has underlying'Upper Jurassic Oxford Clay' which is suitable for making bricks and in 1935 the Ridgmont Brickworks were built by the Ridgmont Fletton Brick Company.
Split into simpler sentences: The surrounding valley has underlying'Upper Jurassic Oxford Clay' which is suitable for making bricks. In 1935 the Ridgmont Brickworks were built by the Ridgmont Fletton Brick Company.