There are several photos, eg AS15-88-11870HR, which show the collection of objects that Jim Irwin left on the lunar surface. As the ALSJ states:
In his book To Rule the Night, Jim wrote "There were a number of things we left on the Moon purposely. I left some medallions, flat pieces of silver with the fingerprints of Mary and our children. And as a result of a letter that I got two months before launch, I also left a small portrait of J. B. Irwin. A young lady sent me a picture of her father, J. B. Irwin, saying that he had talked about his desire to go to the Moon all his life. He died a seventy-five, before the first manned landing. I thought it would be a gracious gesture to take J. B.'s picture and leave it on the Moon."
I'm curious about what the two octagonal objects are. They appear to be transparent. Are they two halves of a glass or plastic case for the medallions? (One appears to be just below the more distant of the two octagonal items.
I don't know what the octagonal items are; however here, off topic, are some other things left behind by the Apollo 15 crew.
According to
http://mentalfloss.com/article/84049/7-strange-things-have-been-left-moon and
https://futurism.media/weird-things-that-have-been-left-on-the-moon, Jim Irwin and David Scott left:
Fallen Astronaut, a 3.3-inch aluminum model placed on the surface by the crew of the Apollo 15. Along with the sculpture, there is a plaque bearing the names of eight American astronauts and six Soviet cosmonauts who had died in service; and
a small piece of solidified lava on the moon. The chunk of rock was taken from Devil's Lake near Bend, Oregon; and
a small plaque containing the words, “This is to certify that The University of Michigan Club of The Moon is a duly constituted unit of the Alumni Association and entitled to all the rights and privileges under the Association’s Constitution.” (Irwin, Scott, and Alfred Worden--the CMP--attended Michigan)
Leaving the sculpture turned out to be
scandalous, as the artist, supposedly despite an agreement with the crew to the contrary, advertised for sale replicas of the piece. NASA successfully pressured the artist to withdraw the offer.
