Sunday, October 31, 2010

Juvenile heteromorph

Another small heteromorph from the Cretaceous Mancos Shale. This one has the body chamber preserved so it is freshly hatched or up to a few weeks old. 1mm diameter at widest point.

Tuesday, September 21, 2010

SR2 Anasibirites Bed

Like at all other localities, about as thick as the hammer. The lower beds at this locality are a lot less fossiliferous than at any other, they have also been baked by the nearby igneous intrusions, so I don't think they are worth collecting in detail.

A closeup. All the small circular spots are drippings from the Pinyon tree above

Monday, August 23, 2010

Tirolites ?

? Tirolites body chamber cast

From above the "Clam Wall" and below the "Spathian Gap", geographic outcrop nicknames that don't mean anything to anyone unless you have a copy of my field notes from 15 years ago, sorry. Even below M109 of anothers' notes. Not a very good fossil, but it may be important.

Tuesday, August 17, 2010

Calcite Heteromorph

A small portion of a heteromorph ammonoid, possibly Allocrioceras. This thing is only about 1.5mm long, photo taken through the eyepiece of my microscope. Dorsal side toward viewer, without impressed zone so it was completely evolute and probably open whorled, not enough preserved to tell if it was helical or not. From the Upper Cretaceous Mancos Shale, lower Upper Turonian Scaphites whitfieldi Zone.

Wednesday, June 16, 2010

Rudolftruempyiceras Guex & Bylund 2010

The name Boreoceras Dagys & Ermakova (1988), has been replaced with Rudolftruempyiceras Guex & Bylund 2010, Family Columbitidae, see Guex, J., Hungerbuhler, A., Jenks, J., O’Dogherty, L., Atudorei, V., Taylor, D., Bucher, H., Bartolini, A., 2010, Spathian (Lower Triassic) Ammonoids from Western USA (Idaho, California, Utah and Nevada), Memoire de Geologie (Lausanne), No. 49, on page 29. The name Boreoceras is used for an Ordovician Endocerid Nautiloid by Miller & Youngquist (1947). The ammonoids in this old post and this update, will probably be referred to Xenoceltites and not the new genus.


Thursday, June 3, 2010

Cephalopods - Present and Past

Cephalopods - Present and Past:

Stephen, D.A., Bylund, K.G., Bybee, P.J. and Ream, W.J.: Ammonoid beds in the Lower Triassic Thaynes Formation of western Utah, USA, p. 243-252

In the 20 years since I located the Triassic fossil bearing beds in the Confusion Range of western Utah, I have only co-authored papers on sponges and gastropods. Now, a paper on the Ammonoids. The first of many I hope.

Sunday, April 18, 2010

Calcite Replacement

Calcite replaced ammonoid shell
(is that really angular coiling in the umbilicus?)

another showing partial suture line

Tuesday, March 30, 2010

Early Triassic Lilliputians


Just for comparison, the typical size of previously studied Early Triassic gastropods with a Dime for scale.

Wednesday, February 10, 2010

Early Triassic Gullivers

Gullivers from a Lilliputian world
Article abstract

I have been walking on them for almost 20 years, so I knew they were there, I new they were big, and I knew their age, I didn't realize the whole story. I had tunnel vision, only seeing the ammonoids and occasionally looking at the Lilliputians in the overlying beds. The last few years have been different, looking at the other fossils a little closer, they all have a story to tell.
Its OK to have a favorite, or specialize in a certain taxon, but also take a good look at everything else, it's all very informative.

Sunday, January 17, 2010

Placenticeras syrtale

Placenticeras syrtale prepared and ready for display

It may end up in the John Wesley Powell River History Museum in Green River, Utah

Saturday, January 9, 2010

Conglomerate again

On the south end of the outcrop is this conglomerate with some very large cobbles. There are few places where this bed rests on a limestone bed full of chert nodules, and a place where the calcarenite beds rest directly on top of this bed. The matrix looks like the calcarenite but a little more analysis is needed to verify.

The hammer is sitting on top of the Conglomerate, the beds above are the calcarenite. The hill in the middle distance is capped with the conglomerate (the dark rock), it was mapped as the Thaynes Formation back in the last century, all the rest is Permian.

The conglomerate on top of the hill. Limestone with chert in foreground. Both dip toward the NE, toward the axis of the syncline. The beds in the previous picture dip north, along the axis.