The "chili pepper" reference is probably obvious, but just in case, this is what it's based on. In the screen shot at the top, it even appears to have the curved stem — although that's an optical illusion.
It's worth pointing out that Split Rock appears again in the background in the above shot — directly above the second of the three horses — but it's easy to miss because the angle downplays the split.
Here's another view of Walnut, from the Republic serial "Secret Service in Darkest Africa" (1943). Until recently, Walnut remained a compelling mystery — I was pretty sure it was gone, but there was a chance it was hidden behind a mobile home. More recently I was able to put that mystery to rest, and, sadly, confirm that Walnut no longer exists. A mobile home now occupies the spot where Walnut previously stood.
Here's a regular walnut, for comparison. I think the textures are pretty similar, and the Iverson rock even has that horizontal "seam."
Chili Pepper turns up again in Monogram's 1942 Range Busters movie "Arizona Stagecoach," above. The context again places it in the mobile home village area — and this shot finally convinced me that the wedge rock seen in this location is in fact Chili Pepper. I don't think Chili Pepper survived the construction of the mobile home park, but I've only recently discovered its general location, and I'll have to snoop around a bit to make sure.
Here's where it gets interesting (if you find this sort of thing interesting). This is another shot from "Rocky Mountain Rangers," and it shows Chili Pepper and Walnut from a different angle — so different that you would never know they're the same rocks unless you're inclined to spend hours poring over this stuff in excruciating detail (guilty!). But that's Chili Pepper in the front and Walnut behind it. The shot looks more or less toward the west, with the expanse of Sheep Flats behind the riders, Cactus Hill in the background (including a nice view of its rockiest section) and the line of trees that bordered Sheep Flats to the west. The flat area is filled with mobile homes now, the line of trees is almost entirely gone and the 118 Freeway has cut through the area, but you can still see Cactus Hill, as in the shot below.
Continuing to view the Chili Pepper area from different angles, this shot is from the 1941 PRC installment in the Lone Rider series "Lone Rider in Ghost Town," starring George Houston. The shot's a little fuzzy, but it looks down on Chili Pepper from the rocks to the east and a little south, so it aims more or less northwest. That's Chili Pepper at the left — no longer looking anything like a chili pepper — with a tiny portion of Walnut behind it. The rock at the top right, below the tree, is End Rock, which is a familiar feature to Iverson researchers — and which has apparently been preserved as a decoration of sorts in the mobile home village.
Here's End Rock today in its "rock museum" — the centerpiece of a planter out in front of the Indian Hills Mobile Home Village's rec room and pool area (not visible in this photo). I'm not sure what was done to End Rock to make it fit the setting — whether it was tilted, chopped, "cleaned up" or simply replaced — but to my eye it doesn't look much like it did in the movies. For one thing, it seems to have lost the curved top that always characterized it. To be honest, I've never been entirely convinced it's End Rock, but that's what a number of experts have said — and it's in more or less the right spot. At any rate, this is what it looks like now from the southeast, from somewhat the same direction as the "Lone Rider" shot above, albeit from a much lower angle.
This view of End Rock today — or what we call End Rock these days — is from the other side, from the northwest, and I think it shows what the park designers were going for — placing the rock in what is admittedly a picturesque planter setting. That's End Rock (or a reasonable facsimile) near the center of the photo, with part of the mobile home park's rec room visible at the right. A couple of other famous movie rocks can be seen as well: Range Rider Rock, sticking out above the mobile home at the center of the shot, and Corner Rock at the far left. Corner Rock, which was "shaved" to make room for the road, was commonly seen in the movies in tandem with End Rock, usually shot from the other side — from the south — with many a stagecoach, rider and chase group arriving between the two rocks.
A closer view of Corner Rock shows how it was modified to make room for a wider modern road, separated from the mobile homes by a low wall. Toward the bottom of the rock, a chunk of it was chipped away to get it out of the way of the road.
A number of the movies featured in this post are exceptional Iverson productions and deserve to be highlighted: "Rocky Mountain Rangers" (1940), "The Lone Rider in Ghost Town" (1941), "Shadow Valley" (1947) and "The Hawk of Powder River" (1948) are all on my list of "Great Iverson Movies." (Note that in this case the term "great" refers to the quality of the rocks and other Iverson features seen in the movies, not necessarily the quality of the acting, direction, script, action sequences, etc. However, typically the camera work in these movies is really good.) Check out the links above to Amazon if you're interested in snagging copies of any of these. Not all of them are available, but I've included a few links to what I think is good stuff. The 2-DVD set with "Hawk of Powder River" and "Stage to Mesa City" — another really strong Iverson movie — is an especially good deal.