USGS site assistance

[hrguy54]

I use this site  https://mrdata.usgs.gov/geology/state/map-us.html#search-results to see what formations my collecting sites are in. But, due to my lack of knowledge (?) it only helps so much.

When I click on the map at the collection site location I get this type of data :

Record ID	Name	Comment
OHOdl;0	Drakes, Whitewater and Liberty Formations, Undivided	Ordovician
OHOgm;0	Grant Lake and Fairview Formations, Miamitown Shale, Undivided	Ordovician
OHOwa;0	Waynesville and Arnheim Formations, Undivided	Ordovician

 

I interpret this to mean that all 3 formations are represented at this site. In this case, standing at the site I can visibly discern 2 very different areas, one above the other. But that isn't typically the case.

 

Can anyone give me some guidance or point me in the direction of how to interpret this information?  Is there a better place to go to figure out the formations?

[Tidgy's Dad]

Yes, it means the formations all occur at this site. Undivided means that each formation hasn't been broken down into smaller units, such as members, in this locality. 

Sometimes, the formations are clearly distinct, but other times they may blend smoothly into one another, and only the presence or absence of certain fossil markers will help distinguish the beds. 

Some useful info on most of these formations and their fauna can be found here :http://strata.uga.edu/cincy/index.html

 

 

[erose]

"Undivided" on a map means that the units (members, formations or even groups) listed are all likely present but the map scale doesn't allow for them to be shown as individual units (colors).  This is where you need to find the written descriptions of the units to tell them apart.  This is also where some of the online maps fall short. They often have abbreviated descriptions. You need to look at the papers or maps that they reference for detail.  These will describe things like rubbly bedding versus even bedding or all limestone versus a Limestone with shale partings.  Hopefully this will help.

 

As mentioned fossils can also help, but in the Cincinnatian the majority are found throughout.  

 

Go to the ODNR publications page. My favorites are the ones published as field guides to geologic conferences.  There are a handful specific to the Cincinnatian.  Do the same for Kentucky and Indiana.

[Tidgy's Dad]

1 hour ago, erose said:

"Undivided" on a map means that the units (members, formations or even groups) listed are all likely present but the map scale doesn't allow for them to be shown as individual units (colors).  This is where you need to find the written descriptions of the units to tell them apart.  This is also where some of the online maps fall short. They often have abbreviated descriptions. You need to look at the papers or maps that they reference for detail.  These will describe things like rubbly bedding versus even bedding or all limestone versus a Limestone with shale partings.  Hopefully this will help.

 

As mentioned fossils can also help, but in the Cincinnatian the majority are found throughout.  

 

Go to the ODNR publications page. My favorites are the ones published as field guides to geologic conferences.  There are a handful specific to the Cincinnatian.  Do the same for Kentucky and Indiana.

The Cincinnatian. has many common species that only occur only in some formations, or indeed, members. 

With a decent hash plate, it is possible to narrow it down considerably, if not precisely. 

For example, i was able to confirm this hash plate was Liberty Formation due to the brachiopods , bryozoans and crinoids present :

 

[hrguy54]

6 minutes ago, Tidgy's Dad said:

The Cincinnatian. has many common species that only occur only in some formations, or indeed, members. 

With a decent hash plate, it is possible to narrow it down considerably, if not precisely. 

For example, i was able to confirm this hash plate was Liberty Formation due to the brachiopods , bryozoans and crinoids present :

 

 

This looks exactly like materials I'd find at one of the sites in question. I find the Leptaena (valve with ring pattern) at only that site.

[Tidgy's Dad]

1 hour ago, hrguy54 said:

 

This looks exactly like materials I'd find at one of the sites in question. I find the Leptaena (valve with ring pattern) at only that site.

Hmm. 

Leptaena species occur in several Cincinnatian formatiosn. 

This species, Leptaena richmondensis occurs in a few. (at least four) 

What you have to do is look at the other species, too. 

 

[erose]

2 hours ago, Tidgy's Dad said:

The Cincinnatian. has many common species that only occur only in some formations, or indeed, members. 

With a decent hash plate, it is possible to narrow it down considerably, if not precisely. 

For example, i was able to confirm this hash plate was Liberty Formation due to the brachiopods , bryozoans and crinoids present :

 

OK, which species is only Liberty? Everything I see can be found in the Whitewater as well and the preservation can be similar.

 

 

[Tidgy's Dad]

13 hours ago, erose said:

OK, which species is only Liberty? Everything I see can be found in the Whitewater as well and the preservation can be similar.

 

 

Goodness. 

It's rarely a case of "This species is only found in the Liberty, so it's Liberty", if only life were that simple! 

You often have to look at the ranges of different species and slowly eliminate formations. 

So: 

Leptaena richmondensis. Other more unusual species do occur in the Cincinnatian, but these are L. richmondensis. 

Which occurs in the Arnheim, Waynesville, Liberty and Elkhorn.  A paper that links it to the Whitewater in St. Leon would be great,  I believe it may be the case.

Bryozoans : (bottom left of the top right hand brachiopod in the photo) Parvohallopora subnodosa. Belleview, Arnheim, Waynesville, Liberty, Whitewater, Saluda. 

I think it's safe to eliminate Elkhorn at this point as it's not present as St. Leon and doesn't have this species of bryozoan. 

Homotrypella hospitalis. There are three on this surface. You can just about see a couple of 'em to the South West of the Leptaena on the left of the plate. I can give detailed photos if required. Waynesville, Liberty, Whitewater, Saluda. 

Bythopora delicatula. small and not obvious on this hash, but, again, I can provide photos. Arnheim, Waynesville, Liberty. (not Whitewater). 

We are already pretty much limited to Waynesville or Liberty, but I will continue : 

Brachiopods ; Hebertella alveata. Admittedly, most obvious on the reverse of this piece. Liberty, Whitewater only.

Hebertella occidentalis This is one of the very few that meets your claim of species occurring throughout the Cincinnatian. 

Zygospira modesta. Another that occurs in a lot of formations. 

Hiscobeccus capax and/ or Lepidocylus perlamellosum. Not sure, but both are in Liberty and Whitewater as well as others. 

Eochonetes clarksvillensis In the photo if you look, one bottom left corner, dark colour, underneath the other dark coloured one. Waynesville, Liberty. (not Whitewater) 

Trilobites : Well, there are bits in here, but they're in a lot of formations.

Crinoids : 

Gaurocrinus nealli. pentagonal stem sections. Waynesville, Liberty. (not Whitewater) 

Xenocrinus baeri. Officially only Liberty, but i have heard convincing finds in the Whitewater, but rare, on my piece pictured it is by far the most common species, tetragonal columnals. 

And there are Cincinnaticrinus that appear in lots of formations. 

So, what is your conclusion, as to this piece? 

 

 

 

 

 

[erose]

30 minutes ago, Tidgy's Dad said:

Goodness. 

It's rarely a case of "This species is only found in the Liberty, so it's Liberty", if only life were that simple! 

You often have to look at the ranges of different species and slowly eliminate formations. 

So: 

Leptaena richmondensis. Other more unusual species do occur in the Cincinnatian, but these are L. richmondensis. 

Which occurs in the Arnheim, Waynesville, Liberty and Elkhorn.  A paper that links it to the Whitewater in St. Leon would be great,  I believe it may be the case.

Bryozoans : (bottom left of the top right hand brachiopod in the photo) Parvohallopora subnodosa. Belleview, Arnheim, Waynesville, Liberty, Whitewater, Saluda. 

I think it's safe to eliminate Elkhorn at this point as it's not present as St. Leon and doesn't have this species of bryozoan. 

Homotrypella hospitalis. There are three on this surface. You can just about see a couple of 'em to the South West of the Leptaena on the left of the plate. I can give detailed photos if required. Waynesville, Liberty, Whitewater, Saluda. 

Bythopora delicatula. small and not obvious on this hash, but, again, I can provide photos. Arnheim, Waynesville, Liberty. (not Whitewater). 

We are already pretty much limited to Waynesville or Liberty, but I will continue : 

Brachiopods ; Hebertella alveata. Admittedly, most obvious on the reverse of this piece. Liberty, Whitewater only.

Hebertella occidentalis This is one of the very few that meets your claim of species occurring throughout the Cincinnatian. 

Zygospira modesta. Another that occurs in a lot of formations. 

Hiscobeccus capax and/ or Lepidocylus perlamellosum. Not sure, but both are in Liberty and Whitewater as well as others. 

Eochonetes clarksvillensis In the photo if you look, one bottom left corner, dark colour, underneath the other dark coloured one. Waynesville, Liberty. (not Whitewater) 

Trilobites : Well, there are bits in here, but they're in a lot of formations.

Crinoids : 

Gaurocrinus nealli. pentagonal stem sections. Waynesville, Liberty. (not Whitewater) 

Xenocrinus baeri. Officially only Liberty, but i have heard convincing finds in the Whitewater, but rare, on my piece pictured it is by far the most common species, tetragonal columnals. 

And there are Cincinnaticrinus that appear in lots of formations. 

So, what is your conclusion, as to this piece? 

 

 

 

 

 

Nice work. Yes, the Eochonetes would suggest to me Liberty as well. Much more going on than I can see easily on the computer. 

[Tidgy's Dad]

1 hour ago, erose said:

Nice work. Yes, the Eochonetes would suggest to me Liberty as well. Much more going on than I can see easily on the computer. 

i do do my research you know, my friend. 

And, yes; the photo is not conclusive.