The “Missouri Masonic Family” tree below shows the bewildering number of rites and degrees in America. All the way on top of the York Rite (left) you see “St. Thomas of Acorn”.
Also the Swedish Rite knows a shell. Here it is on an 8th degree (“Most Illustrious Brother, Knight of the West”) apron.
Top and bottom: Missouri Masonic Family. Year and designer unknown.
Middle: general apron design