Separated from the mainland of Mexico by the Gulf of California and the Colorado River, lies that little known territory of Baja (lower) California. It is a long narrow peninsula that projects about eight hundred miles southeasterly from the southern border of California. Its width varies from about thirty to over one hundred miles, with an irregular coast line over two thousand miles long bordered by numerous islands, and in size is a trifle larger than the state of Iowa. Lower California is mainly mountainous, with irregular plains along the Pacific coast, and smaller plains and valleys along the north coast and in some parts of the interior. In climatic and other physical features the northern part of the peninsula is very similar to southern California, with some local modifications. The southern end of the Colorado Desert crosses the border, and continues down along the northern coast for some distance. Along the Pacific coast a low range of mountains recedes a short distance inland, and continues for some distance. In the southern part of the peninsula they become higher, forming the San Pedro Martir Mountains, which reach a height of over ten thousand feet above the sea. Vast desolate plateaus of black lava, which surround little gem-like valleys, are succeeded by extensive stretches of desert upon which nothing but the cactus will grow. The western coast is bathed by cool waters and fogs, while the eastern shores are washed by the waves of a warm inland sea, and have almost continuous sunshine. Lower California was one of the early discoveries of the Spaniards, and was promptly placed in charge of the Jesuits, whose missionaries were quite successful. They explored all parts of the peninsula and established missions among the Indians, and at the same time introduced many of the crops and fruits of the Old World. They established three main trails throughout the length of the peninsula, one following each coast and the other running near the centre. These roads are to-day the only routes of travel, and, except for short distances, can only be pursued on mule-back. Most of the Indians who formerly inhabited the peninsula have disappeared, and the population to-day is very small. Some of the old mission churches are still in use, while others are represented simply by fragments of ruined walls and choked-up irrigating ditches.