These cute babs are all over the eastern United States where I'm from. They're quite smol (less than 10 mm) and very flat so they can fit between rocks! I'll probably have many pictures of these cuties to come, but for now, here's a larger version of my profile image.
Not sure. Its all greek to me (technically latin). Thats just the official name.
Edit: I misspelled the name last night and I appologize. Its actually Appressa with only one E.
Edit 2: Patera means "bowl" and I can't find a direct translation for Appressa. A more common name for this type of snail is "Flat Bladetooth Snail" The flat part of the name is obvious, and the bladetooth comes from the white bit of bone that grows on their shell opposite the lip once they're full adults. I'll try to get a picture of the "bladetooth" if I can find a dead one in my garden. Live ones have this feature covered by flesh.