These graptolites occur in Upper Ordovician clastic sediments. It would appear that there are at least two species. These are North American (New York).
Hi John,
I think making a rough genus estimation is difficult in this case, because the picture is maybe not usable (not enough magnification and sharpness) and some of the specimens need further preparation in the apikal area (marked in the picture). Additionally it seems like bad preservation (only Impressions/casts?) On a first view I see something reminding me on Normalograptus with one specimen at 10:00, and most of the others show some similarities to Parareteograptus.
You may check Stroch et al 2011 about the Upper Ordovician Graptolites of Nevada and the papers of Palson.
Best regards
Johannes
It's impossible to be sure from this picture unless you already know the rocks in question... but to me they look more like a Diplograptus sp. than Normalograptus; I think the reteograptid-like forms are purely artefacts due to the taphonomy. But all of that may be wrong, without seeing the specimen under a microscope. :o)
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