Bronze triangulation station mark, American, 1915-1920
1915-1920
Bronze triangulation station mark, Canadian, 1920
1920
Bronze triangulation station mark, Canadian, 1920
1920
Bronze triangulation station mark, Canadian, 1920
Bronze triangulation station mark, British, 1910-1920
1910-1920
Triangulation mark, French, 1914
1914
Bronze triangulation mark, French, 1910-1914
1910-1914