It is the largest of the Lion Group and was named by P.W. Norris because of the deep, roaring sound it makes during an eruption. A beautiful blue green hot spring lies about 40 yards southeast of the Lion Group called Heart Spring. Heart Spring on Geyser Hill is named because it is shaped like a human heart, not the valentine variety. With little runoff and a very hot, deep pool, it gently simmers and steams almost unnoticed. A lacy sinter rim defines the edge of the hottest part, and the snow defines the edge of the entire feature.