At the access road from Idaho Falls , Idaho, going east, before you get to the lower part of road of to the left, or north west there are some very interesting formations. I thought these to be of the lava, or basalt material. On closer inspection I found them to be of more a sandstone like material deeply eroded making holes and all kinds of erratic erosional action. these stacks are quite tall, 15-20 feet and higher. easily scared with gelogic hammer. The color of remove pieses is light even gray or white. I thought maybe they could be like the rapidly cooled froth of an erruption, However I think the lava here was from a flow not erruptive. Could you help me idintify and history of such features