Looking across Devil's Churn to the opposite side, the exposure is pretty representative of this area: basalt breccia cut by numerous dikes. I'm guessing here, but the dike above is probably 12-16 inches across. The footing is pretty good in this area, with the sharply fragmented basalt, but green spots, where the spray supports algae, can get slick. And you do NOT want to fall in. On the plus side, I've never heard of such an instance.