Sitting on the rim of the basalt flow here are three objects that the interpretive sign describes as lava balls. These are said to form in the same way as cartoon snowballs: a bit up high breaks loose and rolls down the slope of the active flow, accreting more lava as it goes, growing into a large, roughly spherically-shaped, ball. It makes good sense to me, but the reason I'm putting it into such equivocal terms is that I have never seen the name "lava balls" anywhere else, nor have I seen similar features in photos. I'm not suggesting anything wrong, nor any better explanation, just cautioning a bit of skepticism on this one.
Reading the Wikipedia article yesterday, I found that this lava flow and Lava Butte are about 7000 years old. That's quite a bit of time in human terms, but not really enough in rock terms to allow weathering to create soils that will support plants. We do see some sage and rabbit brush here, but for the most part, it's barren rock. Mount Bachelor to the left, Three Sisters to the right on the horizon, and I think that's Broken Top as the lower peak in the middle.
The interpretive trail on the breach flow at Lava Butte, looking north at that cinder cone. The summit road is apparent, spiraling up the peak. While the flow is pretty fresh, there are some colonizing pines visible.
The closest Jurassic rocks are likely 150 miles away or so, in the Josephine ophiolite along I-5. Nevertheless, we found this Jeep fun, on our visit to Lava Butte. As yesterday, Three Sisters to the right, Mount Bachelor mostly behind the pine to the left.
Looking west from Lava Butte toward the Cascade crest. Three Sisters are to the right on the horizon, Mount Bachelor to the left, and I think that's Broken Top as the peak between them. The late-stage lava flow, which occurred after the cinder eruption, is visible at the foot of the peak. A version run through Paint.Net's autolevel routine can be viewed here.
Looking roughly north-northeast from the top of Lava Butte, Pilot Butte in Bend stands out just below the horizon to the right of center. Of similar sizes, these two cinder cones are both likely to be parasitic cones on the flanks of Newberry Volcano.
Hyperbole and a Half- I have never read descriptions of depression that capture my own feelings in dealing with it as lucid and, at the same time, as funny, as the ones by Allie Brosh. I'm not having any serious issues with the disease right now- beyond housekeeping- but while this is long, if you have someone in your life whose depression is confusing you, you should absolutely read this and try to appreciate what she's saying. Advice, however well and lovingly meant it may be, is more often than not off-target.
A panorama of three photos, taken at Otter Crest State Park. We're looking south here. At this scale, you can't make out the sea cave at Devil's Punchbowl, on the point in the top middle, but full-size, I can make out that dark spot. In response to a G+ query, I guessed that the reason for the ring shape (emphasis on guess) might be that as a lobate toe of the CRB flow responsible for this structure advanced out onto unconsolidated sediment, it hit a weak spot where it could plunge down and into the underlying beds. This in turn might allow a "rip" to propagate away from the initial invasion. So the rings, in this scenario, would echo the original flow front.
There are also some very obvious radial dikes, roughly perpendicular to the rings. The headland we're standing on here is also basalt, well above the raised marine terrace of Devil's Punchbowl and the inn to the upper left.
Photo stitched in Hugin. May 6, 2013. FlashEarth Location. (Cross hairs on viewpoint; the ring dikes should be pretty obvious in the cove to the south.)
Followup: Here's another panorama using the same shots, plus another one, redone with a better approximation of the correct focal length, suppressing much of the odd curvature.