Crowned X and H.S. in a Square .... Any Ideas ?

British Silver Reading Silver Hallmarks
1

Crowned X and H.S. in a Square … Any Ideas? Also there seems to be another mark to the right of the H.S. but I can’t tell what it is.
Crowned x 2.jpg
crowned x 1.jpg

2

Hartford Sterling Co of Philadelphia. See here (and scroll down) for an illustration of the mark including the bit on the right.