Between the heavy pine and silver fir zones towers the Big Tree (Sequoia gigantea), the king of all the conifers in the world, "the noblest of the noble race." The groves nearest Yosemite Valley are about twenty miles to the westward and southward and are called the Tuolumne, Merced and Mariposa groves. It extends, a widely interrupted belt, from a very small grove on the middle fork of the American River to the head of Deer Creek, a distance of about 260 miles, its northern limit being near the thirty-ninth parallel, the southern a little below the thirty-sixth.