A. Gertrude Clark 
Last updated: 22.06.17
All that can presently (June 2015) be gleaned about by internet searching is that A. Gertrude Clark is the one-off composer of Jolly Days March (1896) published by B. F. Wood Music Co., Boston, Massachusetts, USA.
Surfers are welcome to contribute information about this composer.

Further sheet music at DBE: ON HOLD