Willie Park II redid Atlantic City in 1920. Looking over the list it appears Ross was the most active architect during this period. Perhaps he should be included as full member of the so-called Philadelphia school.
Merion East - Wilson/Committee 1912, Wilson/Flynn 1916
Merion West - Wilson 1913
Gulph Mills - Ross 1916
Huntingdon Valley - Original?, Ab Smith 1909-1916 and probably before and possibly beyond). Low/Tillinghast? The Baederwood course attributed to Colt/Allison was largely already there prior to their arrival.
Pine Valley - Crump/Colt 1913-1918
Whitemarsh Valley - George Thomas & Samuel Heebner 1908, Ross 1919
Torresdale-Frankford - George Sayers 1915 (9), Donald Ross 1922
Llanerch CC (Findlay) - B.F. Lewis/George Lindsay 1901, Alex Findlay 1916 and again in 1928
Cobb's Creek - Wilson, Smith, Klauder, Crump, Meehan 1916
Lulu - J. Franklin Meehan/Warren Webb 1912 (9), Donald Ross 1919
Sunnybrook - Ross but built by Samuel Heebner and George Thomas
Old York Road - Jimmy Laing 1910, Tillinghast revisions 1914
CC of Atlantic City - John Reid/HJ Tweedie 1897, Willie Park 1920
Cedarbrook - Tillinghast 1921
Philmont (South) - John Reid 1907-08, Hugh Wilson/Henry Strouse 1914
Bala - Willie Dunn 1901, Willie Tucker 1903
Philadelphia Cricket - Sanders Handford 1895 (9), Willie Tucker/Samuel Heebner 1898, Donald Ross 1915
Philadelphia Cricket (New) - Tillinghast 1922
Overbrook - Ross 1919
Seaview - Hugh Wilson 1913 (18 - same as today's routing), Donald Ross/Wilfred Reid/William Connellan 1916 (additional bunkering)
Lancaster - Not verified but I believe J. Harold Wickersham/George Franklin 1913, followed by Flynn 1919 through the rest of his life.
Ashbourne - J. Franklin Meehan 1922
North Hills - J. Franklin Meehan 1913, Hugh Wilson/Ab Smith/William Flynn 1916
Aroninmink - Tillinghast/Klauder/Calvert 1913-15 with a hole or two advised by Vardon/Ray during a visit.
Springhaven - Ida Dixon 1903, HH Barker
Green Valley - Willie Park Jr 1919