Mystery photos inside Cullum's "The Night-Riders"

A worn copy of Ridgwell Cullum's¹ early 20th century novel "The Night-Riders" (A Romance of Early Montana) was about to leave our house last week with some other used books when, inexplicably, I pulled it from its box and leafed through it one more time.

This time around, I discovered that someone had pasted a pair of photos on the opposite side of one of the book's glossy illustrations.²

The photo of the mystery woman sitting on some rocks is 2½ inches wide by 4¼ inches deep. Underneath it is an upside-down sliver of another photograph, featuring only a man's head. Odd!

The only potential clue comes from the name and other information written in cursive on the book's first page:

Gerland G. Steck
Co. L, 10th Inf
Fort Benjamin Harrison
(Aside: The 46th Infantry Regiment, which served in World War II, was originally organized in 1917 at Fort Benjamin Harrison from the 10th Infantry, of which Steck was a member.)

But there's no way to know for sure if these two photos have anything to do with Steck or his relations.

Would these two people have been happy to see their faces side-by-side like this?

Footnotes
1. According to a short biography by John F. Barlow on imdb.com, Ridgwell Cullum was the pseudonym of British author and adventurer Sidney Groves Burghard (1867-1943). An excerpt of the biography:

"He was born in London, England on August 13, 1867 where, as a young man not yet eighteen, he chose leave England to prospect for gold in the Transvaal region of South Africa. Later he traveled to the Cape of Good Hope, where he became involved in the conflict between British and Boer settlers. Soon though, news of a gold strike lured Burghard to the Canadian Yukon. ... In time he would settle down and become a prosperous Montana cattle rancher. In 1889 Burghard enlisted in the US Army and may have been involved in putting down the Sioux Indian uprising of 1890-91. Burghard finally found the gold he was searching for after he published his first book 'Devil's Keg' in 1903."

Six of Cullum's novels were adapted into movies. That includes 1922's "The Night Riders," which featured an actor named Goober Glenn in a minor role.

2. Here's the illustration that's on the reverse side of the page that features the pasted mystery photos: