If you walk around the city of Oxford, where we are today, and have a look at the brickwork, which I've enjoyed doing in the last couple of days, you'll actually see that a lot of it is made of limestone.
Hvis du går en tur i byen Oxford, her hvor vi er i dag, og kigger på murene som jeg har nydt at gøre de seneste par dage kan du se at meget af det faktisk er lavet af kalksten.