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Equilateral Prism 2.5

Equilateral Prism, 2.5" (63mm) Length, 2.5" (63mm) Faces - Trian

$11

Equilateral Prism, 2.5" (63mm) Length, 2.5" (63mm) Faces - Trian

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Product Description

Science education products incorporate applied math and science principles into classroom and homeschool-based projects. Teachers in pre-K, elementary, and secondary classrooms use science education kits and products alongside science, technology, engineering, and math (STEM) curriculum to demonstrate STEM concepts and real-world applications through hands-on activities. Science education projects include a broad range of activities, such as practical experiments in engineering, aeronautics, robotics, energy, chemistry, physics, biology, and geology.

EISCO Scientific manufactures and supplies lab equipment for education and industry. The company, founded in 1968 and headquartered in Rochester, NY, meets International Organization of Standardization (ISO) standard 9001: 2000.

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Single equilateral prism measuring 2.5" (63mm) long. Each face measures 2.5" (63mm). Made of durable, highly polished acrylic. Excellent tool for optical experiments, and can be used for photography lighting effects as well. Prisms will create a nice rainbow (even in room light) by using the simple led light of a smart phone. User will need to create a small slit in a black piece of paper and use that slit in front of the led which will create a light ray. The prisms will then refract the white light and create a nice rainbow on a target away from the prism. The farther away you move the target the bigger the rainbow gets and the more distinct colors the user can see. A great tool for teaching optics or for just having fun.

Eisco Scientific started over 50 years ago as a small, family-owned manufacturing company serving the science education marketplace. Since then we have grown into a multinational corporation with headquarters located in both India and the United States that serve hundreds of distributors in over 100 countries throughout the world. Our mission is simple; to be TRUSTED by educators, researchers, and scientists throughout the world to design, manufacture, and DELIVER products that allow LEARNING and the development of scientific knowledge.

We produce over 6,500 unique product lines for the science education and scientific research markets. Our core product lines include:

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Equilateral Prism, 2.5" (63mm) Length, 2.5" (63mm) Faces - Trian

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Sunday, September 26, 2021

Your Friends The Titanosaurs: Menucocelsior arriagadai

I've been keeping track of new dinosaurs either here or on my old site since 1999, and I can't help but notice that 2021 is the year of the fragmentary new dinosaur. Is this a reflection of COVID restrictions at museums and so forth, i.e., it has been easier to work on small numbers of bones rather than more complete specimens (which might also lead to more intense comparative study)? Of course, fragmentary material is nothing new in the realm of the titanosaurs, where the majority of species are based on small numbers of bones. (2021 has been pretty good for titanosaurs.) Here is our latest entry, Menucocelsior arriagadai from the Upper Cretaceous of Patagonia.

Genus and Species: Menucocelsior arriagadai. "Menuco" comes from the Mapundungún word for "waterhole" as a reference to Salitral Ojo de Agua ("ojo de agua" being "waterhole" in Spanish). "Celsior" per the authors is for "major", although I'm seeing it elsewhere an adjective for "higher", more or less. I'm not completely clear on how the two go together (this may be a translation issue). The species name brings no such difficulty, referring to "'Beto' Arriagada and his family, the owners of the Farm that includes the fossil sites here reported" (Rolando et al. 2021).

Citation: Rolando, M. A., J. A. Garcia Marsà, F. L. Agnolín, M. J. Motta, S. Rozadilla, and F. E. Novas. 2021. The sauropod record of Salitral Ojo del Agua: An Upper Cretaceous (Allen Formation) fossiliferous locality from northern Patagonia, Argentina. Cretaceous Research 105029. doi: 10.1016/j.cretres.2021.105029.

Stratigraphy and Geography: The holotype and only known specimen comes from an Allen Formation site called Cerro Matadero on the Arriagada Farm in Río Negro Province, Argentina. The area is known as Salitral Ojo de Agua (Rolando et al. 2021). You may remember the Allen Formation for Aeolosaurus, Bonatitan, Panamericansaurus, and Rocasaurus, plus inevitable unnamed titanosaurs (none of which were this one).

Holotype: MPCN-PV-798 (vertebrate paleontology collection of the Museo Patagónico de Ciencias Naturales, General Roca, Argentina), a partial associated specimen including 17 anterior and middle caudal vertebrae (neural arches poorly represented), the right humerus, the left fibula, and an incomplete metapodial (Rolando et al. 2021).

Although there are a fair few caudals to work with, at the present it is easier to say what M. arriagadai isn't than what it is. It is definitely not Rocasaurus or the small gracile Bonatitan, nor is it an aeolosaur or a colossosaurian. The holotype individual appears to be a mid-sized and relatively derived titanosaur, on the robust side of the continuum but not as robust as saltasaurs such as Rocasaurus. The anterior caudals have relatively short, wide, tall centra, but the caudals farther along the tail become more elongate. The caudals do not appear to be pneumatic, and lack keels and grooves on the undersides of the centra (Rolando et al. 2021). For now, M. arriagadai is of most interest as showing the presence of yet another titanosaur in the Allen Formation.

But that is not where the paper ends, not at all. M. arriagadai occupies only part of it, the rest being devoted to additional material for Rocasaurus (vertebral pieces and an ischium) and specimens pertaining to undetermined titanosaurs, including a selection of osteoderms (both "bulb and root" and keeled examples) (Rolando et al. 2021). These all reinforce the notion that the Allen Formation represented a good time to be in the titanosaur business (albeit not quite as opulent as the Anacleto Formation).

References

Rolando, M. A., J. A. Garcia Marsà, F. L. Agnolín, M. J. Motta, S. Rozadilla, and F. E. Novas. 2021. The sauropod record of Salitral Ojo del Agua: An Upper Cretaceous (Allen Formation) fossiliferous locality from northern Patagonia, Argentina. Cretaceous Research 105029. doi: 10.1016/j.cretres.2021.105029.

Sunday, September 19, 2021

Marmot Men's Colfax Vest

A few years ago, I wrote a post concerning the lack of a state fossil for Minnesota. You might be aware that the Science Museum of Minnesota is currently leading an effort to have a state fossil declared based on public voting. You can check out the candidates and vote here. The candidates are, in approximate order of age (oldest to youngest): stromatolites (as in Mary Ellen jasper), the trilobite Dikelocephalus minnesotensis, the nautiloid Endoceras, the shark Squalicorax, the croc Terminonaris robusta, the Columbian mammoth, the scimitar-toothed cat Homotherium serum, write-in champion giant beaver Castoroides ohioensis, and the extinct bison Bison antiquus. Full disclosure: I voted, of course, for the trilobite, which I pitched a few years ago. Voting closes September 30, so there's still time to participate.

Sunday, September 5, 2021

Bryozoan Overload

Sometimes you look at a slab, and you notice one special thing about it. "That's a nice Isotelus hypostome." "Neat strophs." "Look at that Phycodes!" In this case, it's "Gee, that's a lot of bryozoans!"

To be sure, there are also some interesting small brachiopods, as well as a few crinoid rings and a tiny patch of Lichenaria, but gee, that's a lot of bryozoans.

(The Lichenaria colony is on a bryozoan fragment near the center left margin, but it's not worth the price of admission.)

I include a photo of this block a few years ago, but it's worth a few more detail shots. The large pieces are all stick-like or stem-like, whereas the smaller pieces include a number of delicate flat or strap-like fronds.

Branching straps plus a few different brachiopods.

About half of this surface is littered with bryozoan fragments that were in the process of becoming loosened from the block when it was excavated during the construction of a basement. Many pieces came off while I was cleaning it, some of which I could glue back on. (Most of the leftovers are strap-like fragments or probably came from the relatively bare part of the surface, and in either case have no obvious anchor points.) Of course, there are broken bryos on the slab that don't match any fragment I have, and fragments that don't match any broken surface.

Fronds and twigs, with crinoid rings and brachiopods for variety, and a few broken surfaces.

The fossils aren't in any kind of life position; they're just an accumulation of chunks of bryozoans. Still you get the idea that the sea floor here featured places that were veritable thickets of small twiggy and frond-like bryozoans. To all you time travelers: probably not recommended for bare feet.

It's bryozoans almost all the way through, as well.

Sunday, August 29, 2021

Further thoughts on the location of Finn's Glen

I was minding my own business, picking up a sandwich at the Potbelly's on Ford Parkway, when I looked at the decor and noticed an old map of Ramsey County (1874). Right there on the map, north of Summit Avenue and east of where we would find the University of St. Thomas today, is "Wm. Finn". William Finn. Finn of Finn's Glen.

Forgive the flare. It was a dramatic moment.

Bingo. Meaning what, exactly? (Unfortunately, it doesn't identify the glen.) Years ago I wrote about Finn's Glen in conjunction with Shadow Falls. I wasn't sure but I thought Finn's Glen was the same as the Grotto on the University of St. Thomas campus, south of Shadow Falls. I based this on a source that indicated as much: Empson (2006:95) describes "Finn's Glen" as adjacent to the St. Paul Seminary, south of Summit Avenue, and a place of meditation. As a University of St. Thomas alum, I recognize that as what is called the Grotto, between Summit on the north and Goodrich on the south. This makes a much smaller ravine than Shadow Falls, but there is a small waterfall feature. Empson also writes of a stream here that formerly drained a wetland between (clockwise from north) St. Clair, Snelling, Randolph, and Fairview. We can see this in Winchell's "Falls of St. Anthony" map (1877). But...

Finn's Glen is clearly marked...

...Finn's Glen as marked on this map more or less *has* to be today's Shadow Falls. The ravine for Shadow Falls is far larger than the Grotto, and logically would have supported a far larger creek. Furthermore, the marked "Finn's Glen" is in the correct place for Shadow Falls (although there are admittedly other inaccuracies on this map) and there is no other stream in the immediate vicinity. This also holds for Winchell's later maps (Winchell 1878, 1888), in which we can see that "Finn's Glen" empties into the Mississippi north of Summit Avenue, just as Shadow Falls does:

From Winchell (1878).

From Winchell (1888).

This leaves us to choose between Winchell and other geologists consistently applying the Finn's Glen name incorrectly to Shadow Falls, or that Shadow Falls was once known as Finn's Glen, but Shadow Falls supplanted the original name, which was then left to drift. Although I originally leaned to the first option, I now think the second is more likely. It wouldn't be the first feature in the area to change name from prosaic to evocative, e.g., Brown's Falls becoming Minnehaha Falls. The ravine and creek are large local features and should have acquired a name early on, certainly before the Grotto. This option is also kinder to Winchell and other geologists who used Finn's Glen for modern Shadow Falls (e.g., Sardeson and Ulrich). Does it fit with the timeline?

Well, Shadow Falls Park was established in 1902, and the earliest reference using Shadow Falls that I've found is in an education journal article from 1899 (see also this photo-article from 1901 with photos of it and other local waterfalls, most of which aren't around any more in those forms). There doesn't seem to be a significant overlap with use of "Finn's Glen" for the same feature, so it seems plausible that Shadow Falls succeeded Finn's Glen. Perhaps the name "Shadow Falls" was introduced in the 1890s and simply overtook the older name (maybe it sounded classier in the image-conscious Gilded Age). Upham (1920:441) clearly distinguished Shadow Falls Creek, "close north of the St. Paul Seminary," from Finn's Glen "about a mile farther south". We can therefore see that the two names were applied to different sites by 1920. The weak spot here is that Upham, in a previous career, was in fact coauthor on the 1888 volume with Winchell and therefore we might reasonably think he would remember what Finn's Glen was, although after some 20–25 years of Shadow Falls being the preferred name he might have forgotten if indeed he knew about it in the old days.

Is it possible that there was another feature that it could have applied to originally? Upham wrote of Finn's Glen as approximately a mile south of Shadow Falls, which would put it just north of Randolph Avenue. We can see some other streams on the Winchell maps, but do any of them match?

Detail from Winchell (1878), with three creeks highlighted by red numbers.

#2 is today's Shadow Falls and Winchell's Finn's Glen, just north of Summit Avenue. #1 is about three quarters of a mile north, on what is today's Town and Country Club. (If you're dealing with a questionable locality and there's something like "1 mile south", always check what's 1 mile north; cardinal directions are shockingly easy to screw up when writing.) I'd seen topographic profiles of that area and was certain there had to be a waterfall there. Well, there was, but it's been gone a long time. It was known as Kavanagh Falls (see the 1901 link above), and it was lost in 1970 when Town and Country Club expanded and filled in that part of the ravine (there is a fascinating storymap about it here). (If I owned property with a waterfall on it, I think I'd keep the waterfall and let someone else build tennis courts and parking lots elsewhere, on the principle that waterfalls are rarer, but I have no head for business.)

#3 is more of a mystery. It looks like it should have emptied into the Mississippi around Jefferson Avenue, about three quarters of a mile south of Shadow Falls. This is not a mile, but it's not unconscionably off, either. This one is even harder to account for than Kavanagh Falls. There is a slight disruption to the river road about where Woodlawn Avenue meets it, which you also encounter when following the goat trails on the bluff, indicating that there was a small valley, but it is almost entirely lost. Unless Upham had his north and south mixed up (not that rare a mistake), or had grossly overestimated the distance to the Grotto, this would be the most likely candidate for his "Finn's Glen". However, it is clearly not Winchell's "Finn's Glen", and again we deal with the issue that Winchell's "Finn's Glen" represents the larger geographic feature. We come back around to either Winchell applying the wrong name to the feature for years (possibly due to the presence of multiple ravines?), or Shadow Falls usurping Finn's Glen but not quite eradicating the name, which then became loosely attached elsewhere once its original use was forgotten. (Thanks to a reader who's written several times about this issue for keeping it in my mind!)

References

Empson, D. L. 2006. The street where you live: a guide to the place names of St. Paul. University of Minnesota Press, Minneapolis, Minnesota.

Upham, W. 1920. Minnesota geographic names: their origin and historic significance. Collections of the Minnesota Historical Society 17. Minnesota Historical Society, St. Paul, Minnesota.

Winchell, N. H. 1877. The geology of Hennepin County. Minnesota Geological Survey, St. Paul, Minnesota. Annual Report 5:131–201.

Winchell, N. H. 1878. The geology of Ramsey County. Minnesota Geological Survey, St. Paul, Minnesota. Annual Report 6:66–92.

Winchell, N. H. 1888. The geology of Ramsey County. Pages 345–374 in N. H. Winchell and W. Upham. The geology of Minnesota. Minnesota Geological and Natural History Survey, Final Report 2. Johnson, Smith & Harrison, state printers, Minneapolis, Minnesota.

Sunday, August 15, 2021

Your Friends The Titanosaurs: Hamititan xinjiangensis

As far as I'm concerned, 2021 has been relatively quiet for new dinosaurs (great year for ophthalmosaurid ichthyosaurs, though; I might even learn to spell "ophthalmosaurid" correctly the first time through). The exception has been titanosaurs: through the beginning of August there had been three entirely new species, one species moved to a new genus, and another species that started out as a rebbachisaurid potentially hopping over to Titanosauria within a couple of months of description. Hamititan xinjiangensis makes another new addition. It was published this week (Wang et al. 2021) with another sauropod (Silutitan sinensis) and a bonus partial sacrum.

Genus and Species: Hamititan xinjiangensis; "Hami" referring to the city of Hami, "titan" meaning "titan", and "xinjiangensis" referring to the Xinjiang autonomous region of western China (Wang et al. 2021). Together they mean something akin to "Hami titan from Xinjiang".

Citation: Wang, X., K. L. N. Bandeira, R. Qiu, S. Jiang, X. Cheng, Y. Ma, and A. W. A. Kellner. 2021. The first dinosaurs from the Early Cretaceous Hami Pterosaur Fauna, China. Scientific Reports 11:14962. doi:10.1038/s41598-021-94273-7.

Stratigraphy and Geography: H. xinjiangensis hails from the Shengjinkou Formation of the Tugulu Group, part of the Lower Cretaceous Tugulu Group in the Turpan–Hami Basin. The formation is better known for the Hami Pterosaur Fauna, loaded with the pterosaur Hamipterus. The holotype and only known specimen of H. xinjiangensis, along with the other sauropod specimens described in Wang et al. (2021), came from lacustrine sandstone. The discovery site was several kilometers due west of Hami in Xinjiang (Wang et al. 2021).

Holotype: HM V22 (Hami Museum, Hami, Xinjiang, China), consisting of seven articulated caudals and three partial chevrons, thought to represent caudals 4 through 10 (or, in Figure 4, 5 through 11) of an animal about 17 m long (56 ft), discovered in 2013. A small theropod shed tooth was found nearby (Wang et al. 2021).

Figure 4 in Wang et al. (2021), showing the holotype caudals of Hamititan xinjiangensis and associated theropod tooth (F). Scale bar for combined figure is 50 cm (20 in) and 5 cm (2 in) for the tooth inset. See here for full caption. CC BY 4.0.

Is H. xinjiangensis indeed a titanosaur? It's a fair question, given both the historical difficulties surrounding Early Cretaceous titanosaurs and the particular difficulties classifying East Asian Early Cretaceous sauropods, which seem to be doing their own thing. First things first: H. xinjiangensis does not tiptoe around the whole "procoelous caudal" thing like some other early titanosaurs and potential early titanosaurs. It is boldly, proudly procoelous. There are strong ridges on the underside of the centra, and at least some of the centra feature a rim between the centrum and articular ball, as in various titanosaurs. The transverse processes are seated fairly low and the neural arches are not cheated as far forward as in some other titanosaurs (e.g., aeolosaurs). The bones do not feature spongy texture (Wang et al. 2021). Despite some quibbles, it's certainly got more going for it than some other putative early titanosaurs (although I certainly would not be surprised if within a few years someone argued it was not a titanosaur, just another East Asian Early Cretaceous sauropod with a titanosaur-like tail).

Is it Silutitan? Well, we can be reasonably certain that the holotype of H. xinjiangensis is not from the same individual as the holotype of S. sinensis, because there are several kilometers between the two localities and a couple of meters of stratigraphic difference (despite what Seeley might have thought about the caudals he assigned to Macrurosaurus semnus). To look at this phylogenetically, Wang et al. (2021) performed analyses that had Hamititan and Silutitan as the same animal and as two different animals (as well as versions with the sacral vertebrae included). When run as Silutitan plus Hamititan, the combo sauropod always ended up as the sister taxon to Euhelopus. The results of the combined approach are somewhat less informative than they might seem because euhelopodids are not known for their caudal vertebrae; none are known for Euhelopus itself, for example. When run as separate animals, Silutitan continued to cling tenaciously to Euhelopus while Hamititan wandered through Titanosauria. Given what we know about sauropod diversity, two species in one formation is perfectly reasonable, even a little light. (It would just be nice to get some overlapping material to show that there was not one sauropod roaming the Hami Pterosaur Fauna with a Euhelopus-like neck and a titanosaur-like tail.)

References

Wang, X., K. L. N. Bandeira, R. Qiu, S. Jiang, X. Cheng, Y. Ma, and A. W. A. Kellner. 2021. The first dinosaurs from the Early Cretaceous Hami Pterosaur Fauna, China. Scientific Reports 11:14962. doi:10.1038/s41598-021-94273-7.

Sunday, August 8, 2021

Geranosaurus atavus

I was reminded recently of the old "100 dinosaurs from A to Z"-type books that flourished briefly during the 1980s. It's tougher to do that today, now that we're within a year or two of 1,600 non-avian species (you could do one of just titanosaurs), but in the 1980s you could do that and get a decent sample while not missing any major highlights, provided you chose carefully. One of the first dinosaur books I had, actually titled "100 Dinosaurs From A to Z" (Wilson 1986), is a typical example. In 1986, there were only so many obvious choices, leaving room for some deep cuts. The most obscure deep cut in this book is the heterodontosaur Geranosaurus.

Sunday, August 1, 2021

Practical applications of Chesapecten, early 19th century

"Fossil pectens of a large size, some of them ten inches wide, are found abundantly in the lower part of Virginia. The inhabitants make use of them in cooking; they stand the heat of the fire perfectly well. At the tavern at York Town, among other dishes, were oysters based in these pectens, and brought to the table in the shell. I wanted the company of a few scientific friends to enjoy the treat. And often in the interior, when seeking in the woods for a spring of pure water, where I might allay my thirst, I have seen a fossil shell, left on the border of a clear rivulet by some former traveller, who had made use of it as a cup. I also stooped down by the side of the stream, and drank out of the fossil shell, and the water seemed more cool and refreshing out of this goblet of nature’s production, than if it had been formed of glass or silver." (Finch 1833)

Chesapecten madisonius, not quite as famous as C. jeffersonius but still quite nice.

References

Finch, J. 1833. Travels in the United States of America and Canada. Longman, Rees, Orme, Brown, Green, and Longman, London, United Kingdom.