Finding Treasures, Art "Studies"

I'm finding these wonderful "studies" that Dad created, and realize now the lengths he went through to learn his subjects. The time, effort, and energy that went into each of these "studies" must have taken many hours. I know many of these were compiled at "The Academy of Science" in San Francisco, where the scientist allowed Dad to actually go in the back rooms and help himself to any material he needed. (See "In the Eye of the Beholder - Dolly Varden Trout Painting)