Cris

March 2017 Finds Of The Month

43 posts in this topic

12 minutes ago, ynot said:

Just curious, but after all of the above, how would You label it?

 

 

The same way I suggested labeling it before there was any "all of the above". :P

 

Indeterminate ptychopariid.

 

 

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4 minutes ago, piranha said:

 

 

The same way I suggested labeling it before there was any "all of the above". :P

 

Indeterminate ptychopariid.

 

 

"slaps forehead" Oh duh:blush:

 

Thanks Sir.

Tony

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8 hours ago, piranha said:

Known from one fairly complete example and several fragments.

 

Known from *two* fairly complete examples :headscratch:.

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14 minutes ago, EMP said:

Known from *two* fairly complete examples :headscratch:.

 

 

Surely there are many others since Rasetti's paper in 1961 and your find in 2017.  Reinhardt 1974 also mentions finding indeterminate trilobites without elaborating on the details.  It is difficult to quantify the actual totals without having access to collection data at institutions that have Frederick Formation trilobites.  

 

 

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8 hours ago, piranha said:

Surely there are many others since Rasetti's paper in 1961 and your find in 2017.  Reinhardt 1974 also mentions finding indeterminate trilobites without elaborating on the details.  It is difficult to quantify the actual totals without having access to collection data at institutions that have Frederick Formation trilobites.  

 

I doubt it. The area has been built up a lot since the 1960s, and many of the past localities are now homes or shopping centers. Even some of the quarries have closed.

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12 hours ago, piranha said:

...It is difficult to quantify the actual totals without having access to collection data at institutions that have Frederick Formation trilobites.  

 

4 hours ago, EMP said:

I doubt it. The area has been built up a lot since the 1960s, and many of the past localities are now homes or shopping centers. Even some of the quarries have closed.

 

 

There may not be many trilobites to collect now, but they are well represented and documented in institutional collections.

Because they have little scientific value, indeterminate partial trilobites are not recorded with a great amount of specificity.

 

 

Rasetti 1961:

 

 "As there is a variety of cranidia, most of which are poorly known or unknown elsewhere, there is little ground on which to base tentative references of cranidia and pygidia to the same species.  Trilobite fragments from the Dunderbergia zone, especially the beds at locality ccm/4, indicate the presence of other species in addition to those described herein, too poorly represented to warrant illustration."

 

 

Reinhardt 1974: Adamstown Member trilobites - "Locally abundant, poorly silicified trilobites."

 

Also, Brezinski 2004 published some figures of unidentified Frederick Formation trilobites.

 

Rasetti, F. (1961)
Dresbachian and Franconian trilobites of the Conococheague and Frederick Limestones of the Central Appalachians.  
Journal of Paleontology, 35(1):104-124 

 

Reinhardt, J. (1974)
Stratigraphy, sedimentology, and Cambro-Ordovician paleogeography of the Frederick Valley, Maryland.
Maryland Geological Survey, Report of Investigations, 23:1-73

 

Brezinski, D.K. (2004)
Stratigraphy of the Frederick Valley and its relationship to Karst Development.
Maryland Geological Survey, Report of Investigations, 75:1-101

 

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I will also try my hand at the invertebrates!

 

This is a lovely conulariid that I found earlier this month. I just got done prepping him out of his phosphatic cocoon (nodule) that he has been brewing in for 340 million years. It is by far the largest conulariid I have ever found or seen in person. This site has many conulariids, but they are usually a centimeter or less in length. Unfortunately this specimen is not complete, but in life, he would have been really long!

 

What also makes this specimen special is that the 3-dimensional rectangular structure was preserved, which is what it would have been like when it was alive. Other than that they appear to be a type of cnidaria, very little is understood about these creatures.

 

Conularia sp.

Early Mississippian Period (Early Carboniferous)

East Kentucky, USA

White square is approximately 1 cm^2

IMG_20170321_193952.thumb.jpg.73fe9df363e9ad2d8bae6f06750d4f07.jpg

IMG_20170321_194132.thumb.jpg.ab65ed1c757c56897a714b998699f1f4.jpg

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I have been working overtime to come up with some more info on the mystery trilobite.  After a lot of cross-referencing of Quebecaspis faunas of similar age, I finally discovered the undetermined cranidium no. 4 from Rasetti 1961 has been assigned by Eoff 2002, to Tholifrons minutus Palmer, 1968.  By process of elimination, Rasetti's undetermined cranidium no. 4 is the best match with the mystery trilobite.  Tholifrons minutus figures 29-43 are attached for comparison.  

 

IMG.thumb.jpg.1c0392e01e21ec5d0c4c8087a1de9586.jpg

 

 

figures from:

 

Eoff, J.D. (2002)
Late Cambrian (Steptoean) trilobites from the Cow Head Group, western Newfoundland.
M.S. Thesis, University of Oklahoma, 250 pp.

 

Tholifrons minutus Palmer, 1968 - Plate 24, Figures 29-43

The undetermined cranidium no. 4 in Rasetti (1961, p. 120-121, pl. 24, fig. 27) represents T. minutus because its glabella is relatively long (sag), and its palpebral furrows appear to be directed obliquely inward, although it appears to have longer (trans) posterior fixigenae.

 

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2 hours ago, piranha said:

I have been working overtime to come up with some more info on the mystery trilobite.  After a lot of cross-referencing of Quebecaspis faunas of similar age, I finally discovered the undetermined cranidium no. 4 from Rasetti 1961 has been assigned by Eoff 2002, to Tholifrons minutus Palmer, 1968.  By process of elimination, Rasetti's undetermined cranidium no. 4 is the best match with the mystery trilobite.  Tholifrons minutus figures 29-43 are attached for comparison.

 

:D Thank you so much Piranha! This means a lot to me!

 

I've never heard of that genus or species before, that must have really been a lot of digging. :P 

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6 minutes ago, EMP said:

:D Thank you so much Piranha! This means a lot to me!

I've never heard of that genus or species before, that must have really been a lot of digging. :P 

 

 

It was like trying to find a genal spine in a haystack! :oPosted Image :P

 

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Very nice conularid, I always pick them up when I see them, unfortunately that is only probably a half dozen a year. Either not that common or not that well preserved in the Ordovician that I hunt. Based on how fragile the fossils usually are I suspect the later.

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A recent find picked up on 19th March 2017 and prepped this week.

 

The find is a combination of two classic prehistoric marine reptile fossils.

 

Firstly a one and a half inch black plesiosaur tooth, and secondly a paddle digit from a large ichthyosaur.

 

The fossil was found in two pieces and it was only when I got home did I realise they fitted together.

 

Late Triassic

Rhaetian

Aust Cliff Bone Blue Anchor Bed

Westbury Formation

Gloucester

United Kingdom

IMG_0905.JPG

IMG_0909.JPG

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IMG_0908.JPG

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IMG_0938.JPG

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IMG_0939.JPG

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Here is my submission for VFOM.

An extremely rare legless amphibian from the Mazon Creek Deposit.

Phlegethontia longissima Fritsch,1875

Carbondale Formation

Francis Creek Shale (approx 307 MYA)

Collected at Pit 11 March 1st 2017

Concretion split open March 21st 2017

 

Phlegethontia longissima RCMCA0745 (1).JPG

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Phlegethontia

Phlegethontia longissima RCMCA0745 (4).JPG

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Here is my submission for IFOM

A rare Thylacocephala from the Mazon Creek deposit.

The species is Convexicaris mazonensis Schram 1990

Carbondale Formation

Francis Creek Shale (approx 307 MYA)

Collected at Pit 11 March 1st 2017

Concretion split open March 19th 2017

This is one of the best preserved examples ever collected

Convexicaris mazonensis RCMCA0744 (3).JPG

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