Quick hunt in the Main Street Formation of northern Texas

[Aidan Campos]

A short compilation of a quick jaunt into some lower Main Street Limestone (Upper Albian) exposures while doing botany work (my main focus) in the adjacent uplands yesterday, October 3rd.

 

This creek bed exposes the lowermost ammonite zone of the Main Street, the Mortoniceras rostratum Zone (per Kennedy et al., 2005)

 

 

Some of the abundant index fossil for this zone, the widespread Mortoniceras rostratum. Though most of these specimens are obscured by limestone matrix, all have at least the basal remnants of the characteristic rostrum of this species: 

 

 

 

 

 

 

Next, a nice small Peilina quadriplicata oyster with both valves preserved. This specimen is quite weathered in comparison to past material of P. quadriplicata I’ve collected but this species is always a pleasure to find: 

 

 

 

 

From a bit higher in the formation, a small but dense death assemblage block containing Neithea texana, Neithea wrighti, many Plicatula, abundant Cribratina texana forams, and various other things to be examined under magnification later: 

 

 

 

 

Lastly, a wonderful Symphyotrichum oblongifolium growing on the surrounding limestone slope barrens: 

 

[Manticocerasman]

39 minutes ago, Aidan Campos said:

Though most of these specimens are obscured by limestone matrix, all have at least the basal remnants of the characteristic rostrum of this species: 

Nice report

 

Is there no way to prep out the center of the ammonite? or is there no preservation in the middle?

 

[Aidan Campos]

17 minutes ago, Manticocerasman said:

Nice report

 

Is there no way to prep out the center of the ammonite? or is there no preservation in the middle?

 

Thanks! Most of them do appear to have the inner whorls preserved beneath the matrix but I just haven’t gotten around to working on these yet. I definitely will update whenever I get around to them but for now I’ve got a huge backlog of specimens to clean up, photograph, and organize from the past few weeks! 
 

Here is probably the nicest M. rostratum of the day that I gathered after being rinsed off: 

Edited October 5, 2022 by Aidan Campos

[Mikrogeophagus]

Nice to see a fellow North Texan! Cool ammonites  

[Fossildude19]

Nice report and finds!

Thanks for posting here.