Particles of rock silt and sand carried in flowing water are called

They are called grit No, they are actually called grains. If you look it up in Classifying Rocks doc. it will specifically quote that they are called grains. Trust this answer, I have been studying rocks and minerals for a couple months now and I know too much about them and I am almost positive I will never use that when I'm out of school in a couple years. Enjoy.