Saguaro National Park (Figures A and B) offers a variety of spectacular geologic features. Because of the relatively sparse vegetation in the lower elevations of the park, most of these features are easy to recognize and photograph. Some of these features are common throughout the Southwest. Others occur only in regions that have similar geology. This booklet is your field guide to the geology of this magnificent desert and mountain landscape. Most of the geologic features described in the text can be reached by short hikes from the tour roads of the park. This book is written for the visitor who has an interest in geology, but who may not have had formal training in the subject. It may also help ensure that the visiting geologist does not overlook some of the features described.