Chatfield Mn Embedded Fossil Rock

[Bev]

This rock with many embedded fossils is from my first fossil trip a week ago

I stopped at a roadside cut with several hundred feet of rock (horizontal not vertical) exposed, most of it Stewartville layer. So I walked it until I found this. I was on the way to my Mother's, so I only had a few minutes. I thought it was a pretty cool find!

By the way, if you locate Chatfield on a map of MN, SE Corner, and see Hwy. #2, about 2 miles west of Chatfield and 7 miles east of Chatfield (I think 2 might turn to 74 but I could be wrong), anyway toward St. Charles, there are many, many rock outcroppings along the road, almost all of the the Stewartville layer (the only one I can recognize . All of these are available to fossil collectors and will probably yield fossils!

I'm thinking that the embedded fossils are primarily brachs, what do you think?

Bev

[Caleb]

Most of those are brachs, but it's not Stewartville. Most of the rocks in the Chatfield area, especially the areas you pointed out, are Platteville Formation wich is latter part of the middle Ordovician, whereas the Stewartville is in the Late Ordovician. South, West, and North of Chatfield one will start to get into the Galena Formation which contains the Stewartville member in the uppermost layers. Distinguishing the formations can be very difficult especially when dealing with the different members.

[Bev]

Ah, and here I thought I might know one thing....

So, the really pitted rock is not necessisarily the Stewartville layer?

At least I got the brachs right LOL!