Return to the Cannonball River (plus a little Fox Hills)

[Thomas.Dodson]

Over the weekend I tried some new Fox Hills and Cannonball Formation sites as well as returning to a couple old ones.

 

Most of the new Fox Hills site was covered in abundant Ophiomorpha, a decapodian trace fossil very typical for parts of the Fox Hills.

Abundant free weathered pieces of the burrows.

There was a rather large Crassostrea subtrigonalis oyster bed on the property. A common fossil in the upper Fox Hills but I don't often see them in the abundance of this site (fragments in the thousands).

All white/sharp edges you see are oysters.

The Prickly Pears are now fruiting here.

 

I only grabbed a handful of the most attractive individuals. The black/grey sheen on some is very pretty. An Anomia micronema was attached to the matrix on one as a bonus.

 

Edited August 5, 2021 by Thomas.Dodson

[Thomas.Dodson]

To the Cannonball Formation:

 

The Cannonball River is a beauty.

I rarely get photographed since I'm usually alone but this time I have some pics of me on one of the cuts. The one who took the photos didn't want to wade across the river.

Found this oddball hanging on that outcrop.

I always forget to take in-situ pics of the good specimens but here's some afterthoughts.

Drepanochilus species are by far the most common fossil. I collected over 100 this day. Two species are known from the area but I haven't gone through each one yet. Most range from 2-3 cm long.

Euspira obliquata. Largest at 12 mm.

Euspira subcrassa. Largest at 15 mm.

Eopleurotoma? danica is the most common small specimen and has a lot of variation in whorls and sculpture. The biggest of these approach a cm. Most are around 5 mm.

Trying to photograph the wavy sculpture.

Rhombopsis gracilis with the difference in sculpture between mature and immature individuals.

A unique columella that I haven't been able to ID.

Cylichna dakotensis. Hard to photograph these little ones.

Fasciolaria loydi.

Fasciolaria? cordensis. This matches what was tentatively ID'd as Fasciolaria cordensis without ribs as reported in a revision of Neogastropoda of the Cannonball Formation.

Mesorhytis dakotensis.

I posted these from the trip last time but am posting them again since it is the only remaining Cannonball Gastropod from the site. Psilocochlis? occidentalis.

Some Carcharias teeth did crop up this time.

More coral. These all appear to be Paracyathus kayserensis.

 

 

[Thomas.Dodson]

Bivalves were more forthcoming this time although often required significant repair.

 

Dosiniopsis deweyi. 4 more were collected that are likely the same but are missing the hingement.

Partials and internal molds.

Caestocorbula sinistrirostella.

Some Mytilid. I'm leaning towards a crushed Crenella elongata but the compression makes it difficult to ID.

A very poorly preserved Nucula planomarginata but the teeth and nacre are a dead giveaway.

Miltha (Plustomiltha) cedrensis.

"Panopea? cf. Panopea simulatrix"

Arctica ovata.

Crassatella evansi.

I also stopped at an old cannonball site of mine and sifted a free-weathered(!) Camarocarcinus arnesoni crab and a Carcharias tooth out of the sand. This is my first free weathered one, all others have occurred in concretions.

Some other crab elements attached to the matrix underneath.

Compared to my first Camarocarcinus I ever collected many years ago from the same site. I chiseled the first one out of a golf cart sized concretion.

 

 

[Mainefossils]

Looks like you had a beautiful day! Those gastropods are very nice. 

By the way, the caterpillar that you saw look likes a Juanita Sphinx (Proserpinus juanita). 

Happy hunting!  

 

 

[Tidgy's Dad]

Very nice haul. 

[Jeffrey P]

I love your gastropod finds! I would definitely wade the stream for those. In the New Jersey Upper Cretaceous we never find more than a few per trip and always internal molds. Congratulations and thanks for sharing. 

[Thomas.Dodson]

17 minutes ago, Jeffrey P said:

I love your gastropod finds! I would definitely wade the stream for those. In the New Jersey Upper Cretaceous we never find more than a few per trip and always internal molds. Congratulations and thanks for sharing. 

It was an easy wade with a firm bottom and just knee deep with how low the water is right now. That said, I wade streams for a living so other people might be less willing even in good conditions.

 

Those Drepanochilus aren't uncommon finds in the Upper Cretaceous here (Drepanochilus evansi is the species in the Fox Hills) but not in such absurd abundance as this and it is hit or miss on the wing being complete. They're also usually concretionary finds. I was surprised at first by the abundance and free-weathered condition on these. The easy collecting on the Cannonball can spoil you.

[Coco]

I love Drepanochilus !

 

Coco

[ClearLake]

I’m with @Coco, those Drepanochilus are really nice looking. Along with the other finds, that looks like a fun collecting spot.