Those look like Collinista snails - harmless algae eaters. Google images for these snails and see if they match up. If they do, you're ok!
My guess... Trochus
Although it is possible, I don't think these are babies. I am more inclined to think these are some sort of very tiny snail species, possibly (hopefully) mini Turbos (Collonista spp.) which would be a beneficial addition to your tank. Mini Turbos primarily graze on diatoms and microalgae.