Afoot and Afield: San Francisco Bay Area. David Weintraub

      Head north on the Cataract Trail, a wide dirt-and-gravel path, passing a faint trail heading right. The large, grassy meadow ahead and right is called Serpentine Swale, named for California’s state rock, which is found on the upper reaches of Mt. Tamalpais and elsewhere throughout the state. Serpentine soil, rich in magnesium, makes life difficult for many plants, but some have adapted to it and others thrive in it. Later today, you will pass through a grove of Sargent cypress, a serpentine lover.

      The trail descends gently about 100 yards to a fork. Here, the Simmons Trail, used later, goes right, but your route, the Cataract Trail, bends left and crosses a bridge over Cataract Creek, which drains Serpentine Swale and flows into Alpine Lake. Several hundred feet downstream from the bridge, you come to a jumble of big, moss-covered boulders. Although you may see a trail across the creek, stay on the creek’s right side and follow the trail through the boulders.

      Soon you reach a clearing and another wood bridge, this one over Ziesche Creek, named for Edward Ziesche, secretary of the Tamalpais Club, a hiking group founded around 1880. The route turns left, descends a few wooden steps, and then crosses a bridge over Cataract Creek. Just before you reach a large wood bridge over Cataract Creek, you pass a great tangle of evergreen huckleberry that hangs over the creek.

      Passing a trail, left, that crosses Cataract Creek via a large wood bridge, you continue straight. At the edge of a clearing, you meet the Mickey O’Brien Trail, heading sharply right. O’Brien was president of the Tamalpais Conservation Club in the 1920s. Here the you turn right, as the Cataract and Mickey O’Brien trails join for a short distance. Then you follow the Cataract Trail as it branches left and crosses a bridge over a stream.

      Skirting a large meadow, left, you soon reach Laurel Dell Road and the Laurel Dell picnic area. Here there are restrooms, a watering trough, and a place to hitch horses. Crossing the road, you pass through the scenic picnic area, located at a bend in Cataract Creek.

      The Cataract Trail leaves the picnic area from its west side, with the creek on your left. During winter and spring, a waterfall cascades over the ledge of a rocky cliff, downhill and left. The hillside drops steeply here, so use caution: you will have a much better and safer view in a few minutes.

      Two Blues

      The Bay Area has two common “blue” jays, the western scrub-jay and the Steller’s jay. A bird of the forest, Steller’s jay is a dark bird identified by its black crested head and harsh call. The scrub jay, light blue and gray, favors more open country. Both are often called blue jays, but this name is properly reserved for an Eastern species that is only rarely seen on the West Coast.

      At a T-junction, the Cataract Trail turns left, and the High Marsh Trail goes right. Although you will be following the High Marsh Trail from here, you can get a fine view of the waterfall by turning left on the Cataract Trail and walking several hundred feet to a level area near the base of the falls. This route is well shaded, thanks to stands of Douglas-fir, coast live oak, canyon oak, tanbark oak, and California bay.

      Now return to the T-junction and go north on the High Marsh Trail, a narrow, single track. Soon you reach a fork where the trail splits temporarily: stay right. At the head of a narrow ravine, the trail turns left, breaks out of the trees, and traverses a steep, grassy hillside beautifully decorated in spring with California poppies, bluedicks, lupine, and mule ears.

      A steep climb at about 2 miles brings you to a junction with a short trail to Laurel Dell Road, right. The route now alternates between wooded and open areas, and from one of these clearings, a superb view extends northeast to San Pablo Bay and beyond. Beyond this clearing, the trail descends in a narrow corridor through chaparral, in some places via wooden steps. When the manzanita has berries, you can see why it was given a name that, in Spanish, means “little apples.”

      You cross a creek bed, which may be dry, and then begin a steep climb, passing an unsigned trail heading uphill and right. Giving up hard-won elevation, you drop steeply into a ravine that holds a seasonal creek. The trail fights to maintain a contour, but soon plunges steeply among rocks and small boulders to Swede George Creek, named for a mountain man who once had a cabin in the area.

      Now you cross the creek on rocks and follow a rolling course past an unsigned trail, right. About 100 yards from the unsigned trail, you reach an unsigned fork. The Willow Trail descends left, but you stay right and climb on a moderate grade. After topping a ridge, the trail descends to a T-junction. Here, the Cross Country Boys Trail goes right, and your route turns left. High Marsh, a seasonal wetland that may contain a lovely shallow pond, is left.

      The route skirts the marsh and soon reaches a four-way junction, at about 4 miles. You turn right on the Kent Trail and begin climbing. As you gain elevation via steps and nicely graded switchbacks, the hodge-podge of trees and shrubs gives way to a forest of Douglas-fir. Now the trail, rocky and in places indistinct, runs parallel to a stream bed, which is downhill and left.