Vertebrate eggs
Pennsylvanian
Atrasado Formation, Tinajas Member
Kinney Brick Quarry, NM USA.

105mm egg cluster attached to plant stems on 135mm slab. See: Mamay, S. H. (1994).  Fossil eggs of probable piscine origin preserved on Pennsylvanian Sphenopteridium foliage from the Kinney Quarry, central New Mexico.  Journal of Vertebrate Paleontology, 14(3), 320-326.

Fossil fish or amphibian eggs from Paleozoic sediments are extremely rare and otherwise known from perhaps just the Pit 11 Fauna of the Mazon Creek Biota.  The eggs were not shelled and were apparently laid in water.  It appears these eggs belonged to a fish.