At the junc tion of the Hayward fault and the Calaveras fault, Alum Rock Park in San Jo se is a geologist’s paradise: its 20 mineral springs come down throug h Claremont chert; the Briones formation is full of fossils; Berryessa form ation conglomerate greets you at the park entrance and elsewhere. Not surpr isingly, the park is home to a wide diversity of plants, including native o aks, bay laurel, gray pine, holly-leaved cherry, buckeye, coffeeberry, holl y- leaved redberry, blue elderberry, toyon, hillside gooseberry, sticky mon keyflower and blue witch.
Join geologist and botani st Paul Heiple to explore the relationship between plants and the rocks the y grow on. The soil derived from the rocks can be very different from one r ock type to another. The plants are not able to move, so they live or die b ased on what they can get from the soil where the seed fell. This forces th e plants to develop adaptations for these differences, which can lead to sp ecies that only grow in certain conditions. Come explore this relationship and learn how to read the land for plants you will find, the rocks that mig ht be below, the locations of landslides, and the locations of mineral spri ngs.
Beginners interested in basic rock and plant identification are welcome. The hike distance is 2 miles with 600’ of elevation gain. Bring wate r and a bag lunch.