I thought I was trapped at first too, but I felt awfully silly when I saw the green circle next to Clair. You go back to her and walk to that.
blackthorn city
it is behind the gym in blackthorn city
In Pokemon sousilver (I don't know about heart gold )you go to blackthorn city which is located in blackthorn city right across the blackthorn city's gym.
In Blackthorn City.
The last gym badge is in viridian city for Kanto. For Johto it is in Blackthorn city.
By beating the gym leader Clair in Blackthorn City.
the blackthorn city is in the very north east city
Clair is in Blackthorn City, you can battle her straightaway
In the gym at the end of blackthorn city, of course.
Clair is the one who gives you the TM waterfall. He is the gym leader of Blackthorn City.
it is behind the Pokemon gym in Blackthorn City. It is at the back part of the lake behind the gym
you just go north of blackthorn city and beat the gym leader