Fish Fin?

[Prime_Focus]

I found this yesterday and wasn't sure if it was possibly a fish fin. You'll see there is some glacial grinding on the face of the rock but the lines are parallel. Down in the deep groove, the more distinct lines are very small and close together on the left, then fan out and get larger to the right. Any comments would be appreciated. Thanks!

[caldigger]

The glacial scars are neat, shows it traveled for a while.

At first glance, It does resemble a fish fin, but for me it seems like a really deep impression for a fish fin. Of course I'm not a fish expert so there will be others out there that may prove me wrong. We'll let them chime in and give their opinions. 

Interesting piece though. Where was it found?

[Prime_Focus]

It was found in central Iowa. We have a lot of rock in our rivers and stream that bear the scars of being dragged by the glaciers down from Canada. And like this piece, sometimes, the face with the grooves is worn flat.

[Auspex]

The fin-like spray looks also to have been gouged from the rock. I do not think it is an impression.

[Prime_Focus]

I'd thought about that, too, but since the lines fan out quite a bit from one end to the other and also get much deeper, I couldn't imagine glacial action causing that. I also wondered about a plant stem of some kind but I don't know enough about fossils to be sure about anything. Here are some trace fossils that were all along this area. 

[Prime_Focus]

Also, a lot of Lepidodendron

[DPS Ammonite]

Agreed, not a fossil. It looks too fresh, the grooves are  too regular to be from glacial grinding. I am having a hard time trying to see how a glacier could create the canyon with ridges. Look at how sharp the rims of the canyon are. They look newly created. It sort of looks like it was used for sharpening something such as a saw blade. What type of rock is it, a conglomeratic sandstone. Also, show us a photo of the other side.

 

Have you found similar rocks from the area?

 

[Prime_Focus]

Here is a photo of the other side. I was along a man made reservoir. The Zoophycos and Lepidodendron ledges were at different levels up on the cliff face. This rock was right along the shoreline, in a ridge of gravel that the ice had pushed up from the lake over the winter. It looks like a very, water worn piece of limestone. And, no, DPS Ammonite, I haven't found anything like it in this area nor anywhere else. I was actually down in there artifact hunting.

 

Edited April 23, 2018 by Prime_Focus

[westcoast]

Doesn't look like glacial origin, looks more like man-made but no idea how or why...

[DPS Ammonite]

1 hour ago, Prime_Focus said:

Here is a photo of the other side. I was along a man made reservoir. The Zoophycos and Lepidodendron ledges were at different levels up on the cliff face. This rock was right along the shoreline, in a ridge of gravel that the ice had pushed up from the lake over the winter. It looks like a very, water worn piece of limestone. And, no, DPS Ammonite, I haven't found anything like it in this area nor anywhere else. I was actually down in there artifact hunting.

 

If it is limestone (test it with acid) then the scratches can not be old since limestone dissolves relatively rapidly. The rock also could have been caught in a piece of machinery and gouged such as with the treads of a tractor.

[Prime_Focus]

Thanks for the input. I'm more of an artifact person but will pick up nice fossils when I find one. You guys have helped me out on this forum before. I appreciate the knowledge here. 

[Auspex]

4 hours ago, Prime_Focus said:

I couldn't imagine glacial action causing that

I wasn't suggesting a natural origin...
This one smacks of the hand of mechanized man.

[Prime_Focus]

And I agree with what you guys are telling me, Auspex. Like I said, my knowledge of fossils is very limited. Most of what I do know, I've learned on this forum from you guys. I can spot a fake artifact at first glance but sometimes, fossil impressions give me pause.  To my untrained mind, with so many other fossils in the immediate area, I thought it was worth bringing home and asking. There were a lot of coal mining operations in the immediate vicinity back in the 30's thru the 60's so maybe this rock somehow got caught up in some of that activity. Very possible. Again, thanks to all you guys for your help. 

When I see people posting pictures of just plain, naturally formed rocks with a funny shape on an artifact forum, I sometimes shake my head and wonder what they were seeing. Now, here I am............. 

[ynot]

2 minutes ago, Prime_Focus said:

, I thought it was worth bringing home and asking.

Much better than leaving a true treasure in the wilds!

[abyssunder]

The trace fossils are Zoophycos , not Beaconites. Really nice ones !

.......................

Sorry, the ones from the first picture of them.

 

Edited April 23, 2018 by abyssunder
correction

[Prime_Focus]

Yes, I found a small outcropping of these a few years ago and had no idea what kind of fossil they were. I posted a picture f them on here and had an answer within minutes. And then, someone else pointed out that there was a Beaconites barretti trail in one of my pictures. Win, win! I learned two things with one post.  This weekend, I found this much larger outcropping of Zoophycos while hunting for artifacts. It stretches for well over a mile in length and the slabs are covered with Zoophycos. While I was looking in amazement, I remembered the Beaconites barretti and kept watching for an example and finally spotted it. Here is a picture of the larger slab it was on.

[abyssunder]

I'm unsure if the assignment to the ichnogenus / ichnospecies was correct or not in the case of your Beaconites baretti, but it looks good due to the possibility of the  Rhizocorallium-Zoophycos transitional spreite. The resemblance between the pictures below might be very close, leading the hypothesis of B. commune.

 

 

reference:  D. Knaust. 2013. The ichnogenus Rhizocorallium: Classification, trace makers, palaeoenvironments and evolution. Earth-Science Reviews126: 1-47

[Prime_Focus]

Thanks for the information, abyssunder. Again, I apologize but I really am in the learning stage here. I assume by your post that Beaconites barretti is the name assigned to the type of trace fossil shown but it could have been one of many different creatures that made these tunnels. And it sounds like they have been able to determine which creatures made which tunnels by the pattern of debris they left behind them?

 I only got about halfway down along these outcroppings as I was already about 2.5 miles from my pickup and this old man was wearing out fast. Now my interest is peaked and I'm going to go back soon and really take my time and look closely. The Zoophycos was solid, non-stop for the half mile or so that I walked along the rocks and it continued for at least another half mile and possibly farther. Huge slab after slab filled with them. I'll post some pictures of what I find the next time. I was looking for artifacts this weekend but I'll switch gears a little. 

 Here are a couple of pictures from the other ones I found a couple of years ago and someone on here was sharp-eyed enough to point out the Beaconites barretti to me. These are from a different location.  I carried the piece with the quarter on it back home with me. I didn't bring any home this weekend but maybe with a boat, I will.

[abyssunder]

To be honest, I don't think that's Beaconites isp., it looks like a part (a lobe) of Zoophycos isp., because it has continuity at the lower left and the upper right side. Zoophycos is a very complex trace fossil and it has an evolutionary trend in time becoming more lobate and larger.

 

[Prime_Focus]

I'll take you word on this. I really don't know. Someone pointed it out when I posted it three years ago and told me that's what it was. I had never heard of it before and in fact didn't even know what the swirling patterns were. It sounds like it's a pretty varied grouping fossils. Thanks for the information.