Help requested: nominate an easily identified fossil group for inclusion in an ID widget I'm making for judging rock age based on very crude, whole-rock, hand-sample observations of fossil faunas

[pefty]

Help request! I am putting together a tool for judging rock age based on very crude, whole-rock, hand-sample observations of fossil faunas/floras -- the types of observations a child or beginner could successfully make. I view this as a complement to the very fine, species-level identifications commonly employed as index fossils for individual stages, biozones, etc.

In this initial framework, vibrant orange indicates times in earth history to commonly observe the item of interest; paler orange indicates times in earth history to less commonly observe the item of interest. White indicates very little to no practical probability of observing the item of interest. Please keep in mind that the listed indicators are things like "conspicuous horn corals," purposefully declining to address rare encounters with groups of low preservation potential etc.

Got additions/amendments? Toss them in the comments below! Thank you for your insight and assistance.....

[caldigger]

You should probably use a symbol too and not just color. There are a lot of color blind people out there.

[Wrangellian]

59 minutes ago, caldigger said:

You should probably use a symbol too and not just color. There are a lot of color blind people out there.

What do you mean, the orange and pale-orange bars? Shouldn't someone who's colorblind be able to see darker or lighter shades if not the color itself? If there were different colors other than orange used for color-coding, then I would see your point.

[Wrangellian]

1 hour ago, pefty said:

Help request! I am putting together a tool for judging rock age based on very crude, whole-rock, hand-sample observations of fossil faunas/floras -- the types of observations a child or beginner could successfully make. I view this as a complement to the very fine, species-level identifications commonly employed as index fossils for individual stages, biozones, etc.

In this initial framework, vibrant orange indicates times in earth history to commonly observe the item of interest; paler orange indicates times in earth history to less commonly observe the item of interest. White indicates very little to no practical probability of observing the item of interest. Please keep in mind that the listed indicators are things like "conspicuous horn corals," purposefully declining to address rare encounters with groups of low preservation potential etc.

Got additions/amendments? Toss them in the comments below! Thank you for your insight and assistance.....

I like the idea. Not sure you need the word 'conspicuous' for every line - perhaps only a key indicating that the dark orange means conspicuous and the pale orange means inconspicuous (but present), or something like that.

Also I'm not sure I would say that wood/terrestrial plants are conspicuous in the Devonian or even the Mississippian. Maybe in certain rare locations but not widespread. I'd put the pale orange there. Seems like 99.9% of the plant fossils we see on here are from the Penn and later.

[pefty]

Thank you @Wrangellian. Format and wording will definitely change to something easier of the eyes and the frontal lobe as this tool develops. As for land plants and wood, I've never been sure if this is perhaps mostly a bias of the Mississippian paleoenvironments preserved in the North American record. It's always seemed odd to me that we have fossil forests in the Late Devonian of New York, but then all's quiet everywhere until the Pennsylvanian rolls around? Now that it's a question I need to bother to answer soundly, I'm finding that the treelessness of the Mississippian is apparently both global and real. https://www2.humboldt.edu/natmus/lifeThroughTime/Mississippian.web/index.html  Pale orange is it! 

[Mark Kmiecik]

18 hours ago, caldigger said:

You should probably use a symbol too and not just color. There are a lot of color blind people out there.

Make it shades of grey (preferably less than 50) and everyone's on the same page.

[Wrangellian]

5 hours ago, pefty said:

Thank you @Wrangellian. Format and wording will definitely change to something easier of the eyes and the frontal lobe as this tool develops. As for land plants and wood, I've never been sure if this is perhaps mostly a bias of the Mississippian paleoenvironments preserved in the North American record. It's always seemed odd to me that we have fossil forests in the Late Devonian of New York, but then all's quiet everywhere until the Pennsylvanian rolls around? Now that it's a question I need to bother to answer soundly, I'm finding that the treelessness of the Mississippian is apparently both global and real. https://www2.humboldt.edu/natmus/lifeThroughTime/Mississippian.web/index.html  Pale orange is it! 

I would assume that there were forests all over the place from the Late Devonian on, but I guess it depends on your purposes - are you explaining what is known to have existed, or what you are likely to find if you go out fossil-hunting? I've got a total of one Mississippian plant in my collection (from Poland) and none from the Devonian. Got several Pennsylvanian ones, and others have many more than that.

That brings up another complication - you've arranged it in period-by-period blocks, which gives the impression that forests suddenly appeared at the beginning of the Devonian (for example). But again, that depends on your purposes - a rough/general guide, or will it evolve into something more precise? Divide it into epochs? (or I should say systems/series instead of periods/epochs when speaking of the rocks you find the fossil in)

[pefty]

Yeah, it needs to be a tool about what folks will easily find and easily identify. And yeah, I'm planning on keeping it as rough on the chronostratigraphic side as I am on the taxonomic side. It will definitely be true that some groups are very common only for part of the period they're listed for (clymeniid ammonoids, anyone?), but I'm planning to keep it at period scale not only for the sake of ease on my end but also for the sake of keeping engagement at the level at which folks using the tool will most likely want to engage. If (assuming this is an app) the user taps the higher taxon to see its profile, there could be a little more detail there about its stratigraphic and geographic range, just as a wikipedia page for a higher taxon often has a stratigraphic range widget at the top of the sidebar without getting into the nitty-gritty of the stage names etc.

 

As for Mississippian twigs, I've seen my share in the Marshall Sandstone (Osagean) in Michigan. That said, I don't spend most of my time in such nearshore deposits, especially not in the Mississippian when there are such good limestones to wade through. I wonder if the Paleozoic vertebrate folks (or anyone else spending time in nearshore or terrestrial Mississippian paleoenvironments) think of Mississippian plant material as common or not. Ohioans, I'm looking at you!