What is the name of this rock?

I was visiting our local cemetery this weekend, paying my respects to friends and relatives, when I came upon an interesting type of rock. This particular rock, it seems, was a very popular choice for gravestones in the nineteenth century. It looks as though it is particularly prone to erosion, to the point that one can hardly read the inscription on any of the gravestones made with this rock. It’s whitish, and if you rub a finger along it, a few sand-like grains will come off quite easily. What is the name of this rock?

Sounds like it’s going to be limestone or Sandstone of some kind.