Earth Art What kind of rock are you?
It's not necessarily a question one expects to hear in an introductory geology class, but such assignments are standard fare in Professor Ray Pestrong's classroom. Whether freshmen decide they are granite with rough exteriors hiding beauty within or conglomerate rock made up of all they have encountered in their travels, the lessons are designed to help students make connections between themselves and the natural world. Art and music play central roles in Pestrong's teaching. "I use aesthetics to get students interested," he says. "First you need to see the Grand Canyon or a beautiful pattern in rock before you can get into the scientific details of geology. It's that initial attraction that grabs you." For the past 45 years the professor has captured stunning geological images in an effort to bridge the worlds of art and science. His photograph above shows tafoni along the San Mateo coast, the subject of his research for more than four decades. The delicate, intricate sculpture is produced through the natural weathering of sandstone and can be found worldwide along coastlines and in deserts and mountain ranges. Though the formations are shrouded in mystery and are the subject of geological debate, Pestrong has concluded that tafoni forms rapidly, geologically-speaking, meaning in hundreds and thousands of years, rather than millions. But that can be discussed after a good look at the image. | 
