The ancient alluvial fan of central Oakland consists of eight lobes. To refresh your memory since the tour of Lobe 4, here they are labeled on the geologic map. This week I want to show you Lobe 6.
The dominant feature of this lobe is the hill on which the Maxwell Park neighborhood was developed nearly a century ago, but the hills has lesser rises around it defined by stream valleys and a freeway. I’ve named these divisions for convenience as follows.
The southern edge of the lobe is marked by changes in slope above Foothill Boulevard. The changes are definite, but the slopes are gentle. Here it is seen looking up 38th Avenue from Foothill. (All of the photo locations appear on a map at the end of this post.)
And looking down 47th Avenue past Melrose Street toward the bay.
Looking down Trask Street from Cole Street. That’s the Bay-O-Vista hillside neighborhood of San Leandro left of center in the back, and the hills above Hayward in the back center.
And looking down Camden Street from Madera Avenue onto MacArthur, with the trees of Mills College in the back left.
The higher, eastern end of the lobe is not as well defined except on its north side, shown here looking from High Street onto Bayo Street.
The other edges of the lobe are quite a bit more rugged. This is the north side of the Jefferson segment, seen from Gray Street. Just to the left of this frame is the landslide scar of Jungle Hill, which I featured in my post about peculiar Harrington Ridge.
Brookdale Park on High Street, where the Jefferson and Maxwell segments meet, offers a rare glimpse at what the Fan is made of: ancient, well-compacted clay and sand with some gravel here and there.
The Maxwell segment dominates Lobe 6 in height and area. Its steep northern and eastern faces were shaped by stream erosion from below. Here, on MacArthur just south of I-580, it may have been steepened further by development-related excavations.
Seen from across the freeway on Green Acre Road, near the top of the St. Lawrence segment, the spine of Maxwell Hill, about 260 feet high, walls off views of the bay. The dip in the foreground is one of many gulches that punctuate the lobe’s rim.
Lobe 6 is nearly severed in two places. One is where the freeway punches through, having enlarged a pre-existing saddle between the Maxwell and St. Lawrence segments. The other is where Courtland Creek cuts between the Jefferson and Maxwell segments. High Street took advantage of that gap in East Oakland’s earliest days, probably following an older footpath. The gap carved by the creek is visible in this view west down Maybelle Avenue. The church at the left edge is St. Lawrence O’Toole, perched on its namesake segment above the Laurel district.
This view south from High Street shows San Carlos Avenue crossing the valley of Courtland Creek. Courtland Street runs up the creek now, built on the old Key Route right of way.
Other small streams have carved valleys into Lobe 6, but today the valleys only carry culverts and add charm to the topography. The valley of Vicksburg Avenue, separating the Fairfax and Maxwell segments, is the headwater catchment of little 54th Avenue Creek.
More sizeable is the valley of Kingsland Creek, now culverted beneath Kingsland Avenue. This view across the valley is looking north at the north end of Walnut Street. (Did you know Oakland has two entirely separate Walnut Streets?)
Birdsall Avenue, just to the east, also runs up a nice creek valley. These “low roads” running along the stream valleys are your best bets for a pleasure walk, since the streets of Lobe 6 were otherwise laid out in a grid without ridge roads. The nearest thing to a ridge road is 47th Avenue, in the small Fairfax segment. At its top it dips into Vicksburg Valley and offers this view of Home of Peace Cemetery on the Maxwell segment, a pleasant place to visit and an easy landmark to spot from the BART train.
The high streets are a bit awkward to get around on, but they have lots of charming spots. This is where Storer Avenue sweeps around the northernmost rampart of Maxwell Hill, seen from the top of the Herriott Avenue steps.
And of course there’s the postcard view of Meldon Avenue, worth seeing even when Redwood Peak and the high hills aren’t visible.
I always enjoy tramping around here. Photo locations and a hint of the terrain below.
In other news, I will be taking the rest of the month off. Come January, I’ll throttle back my time on this blog, posting biweekly instead of weekly. More details in the Announcements/Q&A page.
Oakland Geology 
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