TonyC Posted September 9, 2018 Share Posted September 9, 2018 My daughter was recently out in Wyoming for a dig (she's the real paleontologist in the family) and brought back these belemnites. These are out of the Sundance Formation. I'm use to the specimens coming out of Big Brook NJ (Mount Laurel formation). I find it interesting that the specimens coming out of Wyoming generally appear larger (length and girth) than their NJ cousins. Also, the Wyoming specimens are more "rockish" looking while the Big Brook specimens have an amber hue to them. Visually, I would say that for both specimens the Outline is cylindrical and the Profile is symmetrical. The Apex varies from acute to more rounded. 1 Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted September 10, 2018 Share Posted September 10, 2018 The Sundance Formation ones seem to be Pachyteuthis densus. The usual species in the Mount Laurel Formation is Belemnitella americana. I think the amber coloured ones are where the guard is nearer to it's original state of unaltered calcite but the more stone like ones are where the outer layers of calcite are being replaced, altered or coated so that they more resemble the calcite in the rock strata it is now found in. 7 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
jpc Posted September 10, 2018 Share Posted September 10, 2018 I agree with most of T's dad's assertions,, but I am not sure the genus of our belemnites out here. Isn't Pachyteuthis a European genus? Neal Larson is convinced there are several undescribed types to be described. Link to comment Share on other sites More sharing options...
TqB Posted September 10, 2018 Share Posted September 10, 2018 6 hours ago, jpc said: I agree with most of T's dad's assertions,, but I am not sure the genus of our belemnites out here. Isn't Pachyteuthis a European genus? Neal Larson is convinced there are several undescribed types to be described. Pachyteuthis densa is the common belemnite in the Sundance Formation. The genus is Boreal and Arctic rather than just European - here's the distribution in the Upper Jurassic (from https://www.academia.edu/11856011/Lower_Jurassic-Lower_Cretaceous_belemnite_biogeography_and_the_development_of_the_Mesozoic_Boreal_Realm) 4 Tarquin Link to comment Share on other sites More sharing options...
jpc Posted September 10, 2018 Share Posted September 10, 2018 well, cool. I stand corrected. Link to comment Share on other sites More sharing options...
The Jersey Devil Posted September 11, 2018 Share Posted September 11, 2018 The Mt. Laurel doesn't exist in Big Brook. The NJ red coloration is probably due to iron absorption/replacement. They look different because they are different species and are from different places. “You must take your opponent into a deep dark forest where 2+2=5, and the path leading out is only wide enough for one.” ― Mikhail Tal Link to comment Share on other sites More sharing options...
TonyC Posted September 12, 2018 Author Share Posted September 12, 2018 22 hours ago, The Jersey Devil said: The Mt. Laurel doesn't exist in Big Brook. The NJ red coloration is probably due to iron absorption/replacement. They look different because they are different species and are from different places. Navesink formation then at Big Brook? Link to comment Share on other sites More sharing options...
The Jersey Devil Posted September 12, 2018 Share Posted September 12, 2018 1 minute ago, TonyC said: Navesink formation then at Big Brook? Wenonah + Navesink “You must take your opponent into a deep dark forest where 2+2=5, and the path leading out is only wide enough for one.” ― Mikhail Tal Link to comment Share on other sites More sharing options...
TonyC Posted September 12, 2018 Author Share Posted September 12, 2018 22 minutes ago, The Jersey Devil said: Wenonah + Navesink Thanks. I'm simply a neophyte who likes to dig and explore. Link to comment Share on other sites More sharing options...
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