Darling Sister,

Today I searched out the sand caves at Rock City in Mount Diablo State Park with Andie. I had vague memories of hiking around in high school, and knew I wanted to find Sentinel Rock. The original plan was to park off the road past the homes, and hike in on Summit Trail. I didn’t see anywhere safe to park so we drove in through the south gate. Only $10 parking for the day. I didn’t get as many steps in as I had hoped, but I definitely got a workout!

FullSizeRenderAndie was brave enough to climb up inside one of the caves.

Copied from www.everytrail.com, here is an explanation of how those caves are formed.

“Mt. Diablo State Park is famous for its stunning sandstone formations, also known as ‘tafoni. Although commonly referred to as “wind caves,” the element most responsible for creating these formations is water. Mt Diablo is probably only 2 million years old at the most, and the caves are only a few hundred or thousand years old. Geologically speaking, the porous sandstone in which these caves form can’t stand up to our Mediterranean climate of wet winters and dry summers for long.

On tafoni structures, you can often see a dark mineral crust called a duracrust. This is what remains of the mineral cement that holds the sandstone together. Brought out by capillary action as rainwater evaporates, it’s then deposited on the outside of the rock. When the duracrust falls off, the sandstone underneath erodes rapidly…”




While following the winding trail, we came across some trees that looked like manzanita, and Andie thought they might be called refrigerator trees, since the bark was cool to the touch. They were unlike manzanita I had seen before. Their bark almost looked like muscles.

Thanks to www.everytrail.com our questions were answered.

“The mountain is home to many endemic plant and animal species, including the Mount Diablo manzanita (Arctostaphylos auriculata), found nowhere else in the world. Some botanists think the peeling red bark of the manzanita is the tree’s way of shedding harmful molds and fungi. The plant flowers early to take advantage of winter rains in our Mediterranean climate.

The Mount Diablo manzanita (Arctostaphylos auriculata) grows only around Mount Diablo. Its blossoms are pinker than those of other manzanita species…”

I knew from past memories that the Sentinel Rock had to be to the North somewhere, and Andie climbed up a boulder to use the panoramic view to spot it.

FullSizeRender-4We followed the trail, which included steps carved into the soft stone. You would have enjoyed the hike.


FullSizeRender-6The view from the top of Sentinel Rock! We made it. Phew! I was worried, there was a woman who was huffing and puffing at the base who said she couldn’t make it to the top and had to come back down.



The steps leading down. Supposedly around 1933 they installed the pipes and cables for a safer trek to the top. Made me wonder how old the initials were that are carved into the rock. (It is illegal to deface any state park property – even though the soft stone is covered with carved initials – don’t be lured into adding your own – not that you ever would!)

IMG_4941The moment Andie brought to my attention that I was crouching in poison oak! F.Y.I There is TONS of poison oak all over the mountain right now. 


The perfect way to end our hike – Ice Monster! Andie introduced me to this Taiwanese shaved snow amazingness. I got the strawberry with bananas and condensed milk syrup. Andie got the honeydew. You really have to try this place, it is like nothing else. One of a kind in our area.

p.s. I bathed myself in Technu and am itching as I am typing this.

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