The image shows different layers of clay, gravel, and sand and how underground waters travel through. HT is the sand surface S is the lowest point where rain water will settle. W is a well that goes as deep as g. O is gravel where water can fill. A and B are artesian wells.
Charles R. Dryer Lessons in Physical Geography (New York, NY: American Book Company, 1901)
Courtesy the private collection of Roy Winkelman