Since my earlier publish, I’ve gone forward and hiked the faceted spur subsequent to the Montclair spur. It holds the Glen Highlands and Merriewood neighborhoods, so I’ve named it the Merriewood spur as a result of Merriewood Drive is the nicest a part of the strolling route.
The 1897 topo map reveals the spur in its clear, unique state between the slim mouths of two wineglass valleys, Temescal and Thornhill Canyons. The Hayward fault runs diagonally via Lake Temescal.
As I detailed in my circumambulation of Temescal Canyon, this a part of city has undergone a severe quantity of human modification since then. But it surely has appreciably affected the ridge route on the spur solely at its northwestern tip, as seen within the digital elevation mannequin.
this picture, I notice that the spur is bigger and extra deeply eroded than the Montclair spur. It’s conceivable, although under no circumstances sure, that the primary incision contains a big landslide. Apart from that the picture reveals no nice secrets and techniques.
The route across the spur is about 4 and a half miles. That is one model that begins and ends on the north parking zone of Lake Temescal Regional Park. The hike alongside the north limb of the spur follows PG&E’s main energy line, and the portion on the south limb follows metropolis streets.
Zoom in on it at gmap-pedometer.com
It’s a climb of about 800 ft. A shorter model might begin from Montclair Village and attain the north finish of the spur by way of Pali Court docket. Or you might strive the model I took, going as much as Broadway from the Rockridge BART station and ending in Montclair (thus qualifying as a ramble).
The remainder of this publish will concentrate on the rocks to be seen alongside the north limb, as a result of in contrast to the Montclair spur, the Merriewood spur contains a wide range of rock models, as proven on the geologic map. I can’t vouch for the accuracy of the map alongside the south limb, the place valuable little bedrock is seen in an informal stroll.
Jsv, Leona Volcanics; KJfm, Franciscan melange with chert and greenstone blocks; KJk, Knoxville Formation; Kr, Redwood Canyon Formation; Ku, undivided Nice Valley Sequence; Tcc, Claremont chert; Tes, Eocene mudstone; Tsm, Sobrante Formation; Tush, unnamed Miocene mudstone.
Right here’s a view of the west finish of the ridge from midway up, simply to the left of “Tush” on the geologic map. I used to be final right here in November of 2008.
It reveals Lake Temescal and the shutter ridge behind it, the PG&E station in entrance of it and the facility line pad carved into the west finish of the spur.
I climbed up from Broadway to the facility line as a result of the footing is fairly good at the moment of 12 months. The clean-cut slope exposes darkish, crumbling shale of the Knoxville Formation. I’m excited to see this perishable stuff.
The western tip of the facility line pad exposes the acquainted rugged, red-stained rocks of the Leona Volcanics.
The contact between these models is vital, however hardly ever uncovered. I need to return and search for it.
Farther up the slope, the rocks change to this sandstone. The boundary between the black shale and the blond sandstone is the enigmatic, long-inactive Chabot fault, and the 2 rocks differ in age by about 60 million years.
The “Ku” unit lumps collectively a bunch of rocks that correspond to a complete set of Cretaceous rocks, the Nice Valley Sequence, that farther south is split into a number of completely different formations. It is perhaps doable to map these models into this a part of the hills, however the final individual to strive, Jim Case within the early Nineteen Sixties, gave up.
Turning round, I noticed the identical set of stones that puzzled me in 2008.
This time my accrued years of expertise, plus the acid bottle I didn’t have with me the final time, advised me proper off that these are limestone, not native to the world (except I and all my predecessors are badly mistaken). They appear to be river rocks which were etched by publicity to our barely acidic rainfall through the years.
Presumably PG&E introduced in a truckload as soon as upon a time for some cause. I additionally visited the previous, deteriorating Horse Hill grime soar and noticed that it had a recent tire observe.
Somewhat farther uphill, the roadbed shows some bedding options — offshore channel deposits, tilted almost perpendicular.
This view appears to be like up towards the highest of the climb proper on the fringe of the “Ku” belt, the place the gentle Sobrante Formation mudstone underlies a long-lived landslide I’ve featured right here earlier than (in 2008 and 2018).
The persevering with collapse of the hillside has opened a brand new entrance. Landslides don’t hand over simply. The continued existence of this strolling route shouldn’t be assured.
That’s the north limb of the Merriewood spur. Having walked it, I can now vouch for the entire circumambulation of Temescal Canyon, and perhaps some day I’ll really hike it multi function go.
This view is from the south limb, close to the underside. Thornhill Street, seen at decrease left, marks the valley of Temescal (previously Kohler) Creek.
We’re wanting throughout the slim mouth of Thornhill Canyon, then throughout the slim valley marking the Hayward fault, then throughout the slim water hole of Dimond Canyon, then throughout the vast San Francisco Bay basin to the Santa Cruz Mountains.
