Where Are The Scale Trees (And Stigmaria) ? At St. Clair!

[hitekmastr]

On our 4th visit to St. Clair, we set a goal to find some of those iconic "scale trees" we keep reading about - the now extinct lycopsid trees with the pock-marked "scaled" trunk and roots. The bark is pock marked with scars left by the leaf stalks and rootlets when they fall off. Did we find Scale Trees? Boy, did we ever!

In addition to the samples we collected, Nancy and I found some incredibly cool samples embedded in large boulders, on the floor of the quarry, even on the trail - these are either fragile or positioned on boulders so they can't be extracted without shattering them, so they are there for any visitors to photograph and enjoy!

We have had wildlife encounters on every visit - a 6 to 8 foot long black snake coiled near a water pool on the trail, fresh black bear tracks on the trail and scat (and a sighting by MZKLEEN the same day we were there), and on this trip a very large spider on the trail (see image).

Fossils On Boulders! - The first "embedded" scale tree fossil (Stigmaria - root with rootlets clearly visible) was located on top of a huge boulder - Nancy discovered it and excitedly called me over to see it. It was bright yellow and very well defined as you can see from the picture. I had to climb on other boulders to reach this one, and took a photo with my rock hammer to show the size and scale (Image 1). It was extremely well preserved but it is exposed to the elements and the top of the boulder is very brittle so it is impossible to extract - if someone tries, it will almost certainly be destroyed. The second sample I discovered on a boulder at the other end of the quarry (Image 2 - you can see my boot on the boulder), and Nan discovered a third which I photographed to show the surrounding woods (Image 3). Finding these and just looking at them was thrilling, like touching history. We hope other collectors leave these as monuments for everyone to enjoy (and don't destroy them by trying to whack off some fragments).

NEW QUESTION: Most of the fossil samples we see online show the scale tree bark with "leaf scars" but very seldom show the leaves attached. How do we know when the samples are roots and rootlets, or branches and leaves? Some of the Stigmaria we collected look like branches or small trunks with leaves but most people are telling me that these are all roots. Would appreciate clarification. What do the scale tree branches with leaves attached look like?

We also saw extremely large trunks of Calamites and Lepidodendron beginning to show through the floor of the quarry near the boulders - this is very dramatic and as more shale wears away the erosion will reveal more of these really large trunks (this is up the slope directly above bottom area with all the large boulders, behind the large boulder covered with white crystals).

It was really cool to find these white and golden yellow-tinged scale tree fossils in plain sight on large boulders - it really brought these trees to life, showing the leaf scars and rootlets that look like thorns spreading directly out from the trunk). Ironically, we didn't notice these scale trees on our first three visits - we did collect a few Calamites and Siggularia bark pieces then, but nothing special. Making Scale Trees (Lepidodendron) our TARGET forced us to focus on this and suddenly, we noticed that they were concentrated in certain areas that we never noticed before.

Nancy found the last embedded scale tree (Stigmaria) fossil right on floor of the quarry trail - it was going to be destroyed by traffic so I checked it out and saw that it appeared to be loose and to my surprise, it popped out in two pieces - this is a cool piece because the pattern is white like most St. Clair ferns. The first photo (4a) shows the fossil embedded in the trail - it doesn't look like much and is actually hard to see (Nancy's keen eyes spotted it right away) - the second photo (4b) shows the recovered fossil.

Collected Samples - We excavated some samples to bring home, and also found some nice samples that other collectors had discarded from fossil pits - you can see how interesting the patterns are. The roots with rootlets attached are not easy to find - as you can see, all of our samples have rootlets attached) - they make nice displays (Images 5, 6 and 7). The two fossils in Image 7 were revealed after segmenting a piece of shale.

Annularia and Calamites - The last Image shows a single rock specimen that shows up in two different colors. It looks like two separate pieces but they are actually attached - the top part shows Annularia including a unique fossil that is a cross-section showing the stem in the center and the leaves radiating out like a star, and lots of smaller fronds. The bottom section shows pieces of the Calamites bark associated with Annularia. This makes for a nice display piece.

We will display these fossils and also use them as illustrations for future articles and maybe a book - we also reinforced our strategy of setting specific goals for each trip, such as looking for a specific type of fossil species, or category, or even just agreeing to aim for a large size display fossil.

This determines how we approach each site, where we explore, and even how we excavate. After 4 visits to St. Clair, we still find it to be new and exciting even as it gets more familiar on each trip - we're sure that you probably feel the same way about your favorite sites, especially if they are close to your home.

Edited September 10, 2012 by hitekmastr

[mzkleen]

You two are becoming regulars there! Very cool. Next time can you take pictures of the large trunks that are poking through? I won't be able to get up there until sometime in early October. You're on track to becoming St.Clair experts. That's great!

[Missourian]

I love how the rootlets are in place.

[Ludwigia]

Nice finds! I'd love to visit that site some day.

[hitekmastr]

You seem to be calling Stigmaria, Lepidodendron. The roots could belong to Sigillaria or Lepidodendron species. They are very close.

You did spot some nice examples of Stigmaria with rootlets still attached. I think there isn't "a place" to find them. They are scattered about.

The limbs are not hard to spot. On the East end of the fossil area is a jeep path, try there, some logs show up exposed there.

Ah! So the appendages are rootlets, not leaves...all of them? I know the roots are called Stigmaria but was thinking this was the trunk which is why I called it Lepidodendron.

This also explains the other small leaf samples which came from a piece of shale I fragmented...these must be the leaves, which I believe are called "Lepidophylloides." Here are the images of those leaves:

Edited September 7, 2012 by hitekmastr

[hitekmastr]

You seem to be calling Stigmaria, Lepidodendron. The roots could belong to Sigillaria or Lepidodendron species. They are very close.

You did spot some nice examples of Stigmaria with rootlets still attached. I think there isn't "a place" to find them. They are scattered about.

The limbs are not hard to spot. On the East end of the fossil area is a jeep path, try there, some logs show up exposed there.

Thanks for the clarification - I modified the original post.

[Terry Dactyll]

Very nice.... I ' think ' the lower images of the '' small leaf samples '' maybe just smaller roots where the rootlets and 'stigmaria 'patina' may not be so well defined at this stage of growth...

[hitekmastr]

Very nice.... I ' think ' the lower images of the '' small leaf samples '' maybe just smaller roots where the rootlets and 'stigmaria 'patina' may not be so well defined at this stage of growth...

I added a question in blue in my original post - how do we distinguish roots and rootlets from branches and leaf scars? Do you have a photo of a scale tree with the leaves attached? Most online images seem to show only the bark with the scars but not the leaves - or - the roots with rootlets. What is the difference between the roots/rootlets and trunk/branches with leaves attached? Thx.

[Auspex]

Leaf scars leave the famous "snake skin" diamond pattern (which has as many variations as there are layers of 'bark'). The rootlets on the rhizomes leave round dimples.

[hitekmastr]

Leaf scars leave the famous "snake skin" diamond pattern (which has as many variations as there are layers of 'bark'). The rootlets on the rhizomes leave round dimples.

Thanks - that's VERY helpful. I also read that the shape of the leaf scars (on the main trunk) helps identify species. What I'm looking for now are examples of fossil scale tree bark with the leaves attached - that's something we'd like to try to find on a future trip.

[Terry Dactyll]

''What I'm looking for now are examples of fossil scale tree bark with the leaves attached - that's something we'd like to try to find on a future trip.''

What I have observed on many crushed shale examples of Lepidodendron is that as the diameter of the branch increases the leaves are no longer present and in its place you have a thin recognisable lepidodendron branch with the leaf scars visible instead... Just as a comparison say if you consider the growth of a modern pine tree, the same principle applies... at some point all the stem and branches have been covered in needles then as the tree grows these are shed retaining the new needles on the thiner branches and tips... Heres a photo of a larger nodular Lepidodendron branch with the leafs still attached and also a tip section thats heavily loaded with leafs...

And just for interest... heres a Lepidodndron tree base showing the transition from basal bark to the recognisable diamond leaf scared trunk....

[hitekmastr]

"What I have observed on many crushed shale examples of Lepidodendron is that as the diameter of the branch increases the leaves are no longer present and in its place you have a thin recognisable lepidodendron branch with the leaf scars visible instead"

Very enlightening. So the larger trunks/bark only have leaf scars, no leaves, because they are shed as the branches/trunk grows, and only the smaller branches retain the leaves. This explains a lot and is not easily found in the literature. It means I won't waste time looking for larger trunks/branches with leaves! It's also helpful to know that the roots (Stigmaria) have round scars compared to diamond shaped scars on the main trunk and branches. It also explains why the leaves remain tiny and concentrated in "umbrella" shaped clusters at the tops of the trunks. Trying to understand all of this so I can focus our collecting targets, also want to look for things out of the ordinary or even rarer samples that might add to the scholarship a bit. St. Clair has almost all the species in one place, from the Carboniferous/Pennsylvanian, considering how many different samples we've collected in just 4 visits, so it's a good place to look for rarer stuff and things that might be "uncommon".

By the way, I examined one entire dug out pit filled with fairly large fossilized trunk/bark samples but all of the textures looked like normal tree bark and "woody" and without leaf scars or grooves. Not sure what that meant. Some of the fossilized soil was light grey and powdery and maybe suggested a "forest fire" - will revisit and photograph some samples to try to understand.

Edited September 11, 2012 by hitekmastr

[Auspex]

...I examined one entire dug out pit filled with fairly large fossilized trunk/bark samples but all of the textures looked like normal tree bark and "woody" and without leaf scars or grooves...

They could have been Cordaites, or they might have simply been heavily decotricated trunks of Lepidodendron or Sigilaria.

If, under scrutiny, there were no signs of parallel grooves or leaf scars, but rather a 'bark-like' appearance, I would think they were the former.

[Eero59]

Yeah, its an amazing site: fossil leaves underfoot everywhere. I've collected hand samples there, but would like to do some minor excavation there to clear a fresh layer, the white pyrophyllite is esp. striking.

[Terry Dactyll]

'' I examined one entire dug out pit filled with fairly large fossilized trunk/bark samples but all of the textures looked like normal tree bark and "woody" and without leaf scars or grooves. Not sure what that meant.''

If you examine the above photograph I took of the insitu Lepidodendron tree closely you will see that the basal bark looks 'woody' and then it changes to the recognisable diamond leaf scars higher up... So if it is casts of the tree bases that was preserved which is often the case... Lepidodendron is also a possibility...

[hitekmastr]

If you examine the above photograph I took of the insitu Lepidodendron tree closely you will see that the basal bark looks 'woody' and then it changes to the recognisable diamond leaf scars higher up... So if it is casts of the tree bases that was preserved which is often the case... Lepidodendron is also a possibility...

I would go with the "tree base" idea, because the pieces seem to be from larger trunks - I am aware that many of the lycopsids/fern trees have different trunk textures at the base and farther up the trunk - as if there isn't enough to confuse us!

[AgrilusHunter]

Thanks fossilcrazy! These are great.

Edited September 13, 2012 by AgrilusHunter

[hitekmastr]

Here is another site with some Lepidodendron terms. If you familiarize yourself with these, your field ID will be a lot easier.

http://www.blackwell...8-9&img=c18f009

These reference materials are terrific - I've added the chart to our library and the book is also an excellent reference. I'm still curious about the leaves - there is a long grass like leaf shown at the upper left corner on the chart - I'd like to see (or find!) a branch or portion of trunk with leaves attached, to see what that fossil looks like. It's very cool that no complete tree has been found or surveyed so there is a lot to find yet! I still think some of the Stigmaria look like branches with leaves rather than roots and rootlets - I guess I'm stubborn - some casts look like leaves and branches and the "leaves" look too fragile to be rootlets...

[Missourian]

One way to visualize Lepidodendron is to compare it to a pine tree. Lepidophylloides is similar to the needles, and apparently Lepidostrobophyllum is analogous to the 'shingles' on pine cones (I had assumed Lepidostrobophyllum were the leaves that grew from the scales on the trunk). Better yet, some pines have smaller branches that have a scaly pattern similar to Lepidodendron. As a matter of fact, there are a few pines down at my place of work that have such branches. I'll have to take a few samples....

[hitekmastr]

I found this online, which adds to our growing scale tree identification reference library:

http://www.daveweb.co.uk/whfossil.pdf

[Missourian]

I found this online, which adds to our growing scale tree identification reference library:

http://www.daveweb.co.uk/whfossil.pdf

Thanks much for this.

One nice thing about Carboniferous plants is that they tend to be the same throughout the world, so a guide for UK plants is useful in far-flung places like Pennsylvania and Missouri.

[AgrilusHunter]

Man hitekmastr, that is a nice pdf! Thanks for posting this, I'll be comparing some of our stuff here to this tomorrow.

[Terry Dactyll]

I found this online, which adds to our growing scale tree identification reference library:

http://www.daveweb.co.uk/whfossil.pdf

It looks like he has used a lot of Hans Steur's specimens from his website here and there...another good site coving plants of all ages....

http://steurh.home.xs4all.nl/home.html#inhoud

[hitekmastr]

One way to visualize Lepidodendron is to compare it to a pine tree. Lepidophylloides is similar to the needles, and apparently Lepidostrobophyllum is analogous to the 'shingles' on pine cones (I had assumed Lepidostrobophyllum were the leaves that grew from the scales on the trunk). Better yet, some pines have smaller branches that have a scaly pattern similar to Lepidodendron. As a matter of fact, there are a few pines down at my place of work that have such branches. I'll have to take a few samples....

One of our goals is to find some Lepididodendron "cones" - however, I noted in one of the referenced images by fossilcrazy - that shows a full tree with all of its elements named - that there seem to be both seeds (carpus) and cones (male and female) depicted on the tree - which adds to the confusion (and intrigue)....

[hitekmastr]

It looks like he has used a lot of Hans Steur's specimens from his website here and there...another good site coving plants of all ages....

http://steurh.home.x...ome.html#inhoud

This is a REALLY helpful site! Lots of real fossil pix, showing the various parts of the scale and fern trees. There is a nice section on Siggilaria. I've been collecting images of Carboniferous plant/tree fossils for my "I.D. book" which we will use to look for specific specimens, especially when we visit St. Clair. All of these posts and referrals are really helping us to better understand the morphology, taxonomy and physical appearance of these fossils. We hope that our somewhat intense and enthusiastic pursuit of answers and clarifications is helping other collectors, as well...