Anza-Borrego North: San Ysidro Mountains

San Ysidro Mountains Above Borrego Springs

The San Ysidro Mountains are the western barrier to Borrego Springs. They are part of a chain, reaching from Banning to Baja California, that is known as the Peninsular Batholith. These mountains were formed millions of years ago when the Baja California Peninsula separated from mainland Mexico and two tectonic plates collided, the North American plate overriding the Farallon or Pacific plate. Evidence of the tortuous twisting, uplifting, and crumbling of rock is easy to see in these mountains.

It's the mountains that make the desert, reaching up to dissipate clouds before they can drop their moisture on the desert sand.

Storm Clouds and Indianhead