Found crustacean in Aptos, Ca.

[C.g.g.92]

Hi so we found this while exploring a creek on a friends farm. Really intrigued and curious to what everyone thinks. 8” across x 6-7” tall 

[DPS Ammonite]

Is the white stuff calcium carbonate? What is the age and formation?

[Fossildude19]

Where was this found? County? Closest city? 

What is the size of this item? Everyone's hands are different sizes. 

 

Please take pictures from all sides, with the camera/phone directly above the item in sunlight.

 

 

[RJB]

Reminds me of some kind of Balanus, or a grouping of such?  Just a guess

 

RB

[caldigger]

6 hours ago, Fossildude19 said:

Where was this found? County? Closest city? 

Aptos is a small hamlet south east of Santa Cruz. 

[Plax]

I'm seeing a clump of oysters or pinna like mollusks. Look at the first pic upside down and you'll see what I mean.

[Boesse]

So this is going to be from the Purisima Formation, a unit that produces virtually no oysters (unlike here in the Carolinas, @Plax - I'm not really sure why; likely owing to the fact that this deposit is open marine). However, barnacle clusters, including quite large ones, are common, and that's likely what this is.

[Plax]

I've provided a great example of folks opining from their personal experience which may or may not be correct. We don't get many 6 inch long barnacle clusters here either which contributed to my mollusk bias. Thanks for the correction Boesse!

[Boesse]

hah, yeah I guess we don't get barnacles that are that enormous out here come to think of it!

 

Now that I've done some reading, it appears as though California has the world's largest barnacle species (gulp) - I never knew that! It's Balanus nubilus:

 

https://en.wikipedia.org/wiki/Balanus_nubilus

[Plax]

and edible! Might try some if I'm ever out there. Thanks for the link and enlightenment.