>>532468781
Why would there be either? A glacier is a huge sheet of ice. I've hiked over three and the only time I've seen chunks of rock is at the bottom where the glacier begins (or the bordering walls of the valley it carved out). A geyser, if present, would be at the very bottom of the ice and would also be a scary weakness as its heat melts a hollow beneath your feet.

Or by did "plain" did you mean the outwash plain? The gravel field left behind when the glacier recedes seasonally?