Northwood 7 CO. #19 Memphis c1908

Found at the thrift store. I didn't notice the little mark until I got home. The mark is an underlined N within a circle. I read about Wright using their mark for a while. Also, that there are similar marks that I are sometimes mistaken for Northwood, where the N almost touches the circle. This one doesn't seem to. Most of what I see of Northwood on the web is carnival Glass. Soo...What do y'all think? Also, what's with the little bubble in the lip and why are those types of flaws not common in modern glass?