
Linda,
Without entering the current political wrangle :D .......... the Jack Russell is a 'type' rather than a specific breed, and is therefore fairly varied in size, colour, etc. and can be either smooth or rough coated. It is a traditionally short-legged dog. This may well be what you've seen, and you've just seen a small one - as my friend who bought one last year to replace her much loved boy who'd died a year earlier found out, though, size of a tiny puppy is no reflection of the dog they may grow into.
There is also a KC registered breed called the Parson Russell Terrier, similar basic type but longer on the leg and a bit 'smarter'.
Hope that helps,
Marina