The St. Peter Formation

A warm and windy spring-day outing to Pacific, Missouri…Pacific is not too far from Spy Garden, but very different from the area where we live. The first sight you see when entering Pacific on historic route 66 is the St. Peter’s Formation:

St. Peter's Formation (and the sign for a car wash)

St. Peter’s Formation (and the sign for a car wash)

These huge rock formations with big, striking “caves” (really old mine entrances) have quite an unceremonious presence in Pacific. There are no signs, no information, no parking (we just parked on some gravel on a side road). I wasn’t quite sure we were even “allowed” to be walking around here!

Uhhh...let's not go inside.

Uhhh…let’s not go inside.

I didn’t know it was even called “The St. Peter’s Formation” until I looked it up when we returned. I knew it was a part of an active mine because a bustling U.S. Silica plant sits right along route 66 just a few “blocks” (rock blocks? haha) beyond where these pictures were taken. Train tracks run right up to the plant and the sounds of train whistles and chug, chugging are steady.

We learned that U.S. Silica is mining “St. Peter Sandstone” and that…

More than 65 million short tons of St. Peter, having an estimated present value of $2 billion, have been mined in Missouri from the 1870s to present.  In 2008, more than 700,000 short tons of St. Peter at a value in excess of 20 million dollars were produced from Missouri.  St. Peter Sandstone was originally used for the manufacture of glass.  Its dominant use recently has been as a proppant in oil and gas formation stimulation nationwide.  There is an estimated 3.8 trillion short tons of St. Peter Sandstone reserves in Missouri. (from Missouri Department of Natural Resources website, click here to read more about the properties of the sandstone)

Not a mile away, there is a little civil war memorial park that does have parking and signage/information. The description of Blackburn Park from Pacific’s website reads,

Home to Pacific’s Civil War replica cannon located on top of Sandstone mountain on 2nd Street off Osage. This is a breathtaking view of Meramec Valley and the civil war cannon are spectacular sites that you will never forget.

That’s a bit of an overstatement. It is a good vantage point, but I wouldn’t call it a mountain. Given, it was cloudy and the trees are still leafless, but still, this view of Pacific isn’t necessarily picturesque.

Though the Spy liked to see the...

Though the Spy liked to see the…

canon.

canon.

Plus it was VERY windy up there, which made it fun.

Plus it was VERY windy up there, which made it fun.

But…

I was way more interested in getting a closer look at those huge rocks down the street!

I was way more interested in getting a closer look at those huge rocks down the street!

Old mine entrances...and can you spy the Spy?

Old mine entrances…and can you spy the Spy?

I don't think we should stand under this over-hang!

I don’t think we should stand under this over-hang!

Can you spot him?

Can you spot him?

Lots of colors...

Lots of colors…

...and textures.

…and textures.

A tree in an old mine entrance, way up!

A tree in an old mine entrance, way up!

Rocks with Tree

Rocks with Tree

Rock face

Rock face

Our favorite part was this big sandy flat area below…Silica Valley, if you will. The kids collected rocks (never, ever underestimate the entertainment value of rocks!)

Silica Valley

Silica Valley

Collecting rocks.

Collecting rocks

Stripes

Stripes

Still collecting rocks

Still collecting rocks

I liked these pretty little (tiny!) weeds growing in the sand.

I liked these pretty little (tiny!) weeds growing in the sand.

St. Peter Sandstone

St. Peter Sandstone

Sharing their finds

Sharing their finds

See you later, Pacific!

See you later, Pacific!

It would be nice to go back on a day when the sky was a good clear vibrant blue (would make for an entirely different set of pictures), but I like how the gray/bright-white sky kind of gave everything a little bit of an otherworldly look today! Happy Friday everyone!

9 thoughts on “The St. Peter Formation

  1. narf77

    Limestone is really beautiful. My hometown was covered with the stuff. None here, all volcanic rock but there is a place in my heart for the majesty and beauty of limestone :)

    Reply
  2. Eliza Waters

    I love geology. It fascinates me to see millions of years of earth history set out before you. Wherever I travel, it is one of the things I always want to know about. It’s kind of creepy how you can just walk right into those entrances. (Your cautious reactions are the same as mine would be!) And even though you didn’t ask, the horticulturist in me has to comment on the tiny plants which look like a type of wild native geranium or possibly cinquefoil (potentilla), both of which would grow in those harsh conditions. Thanks for the wonderful photo tour!

    Reply
    1. Spy Garden Post author

      I have some purple sand I collected on a beach in Connecticut. I took a geology course at Wesleyan and we drove all over looking at different rock formations. I don’t think I was paying much attention at the time, but I wish I had now (or at least taken some pictures) hahaha! Thanks for the plant ID!

      Reply

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