Complex sentence: The first was an apparent clutch of eggs preserved in the sediment that filled in the living chamber of a Jurassic harboceratid ammonite discovered in a concretion that dated back to the toarcian in glacial drift that came from the Baltic region.
Split into simpler sentences: The first was an apparent clutch of eggs preserved in the sediment that filled in the living chamber of a harboceratid dating back to the Toarcian age of the Jurassic period. This specimen was discovered in a concretion incorporated into glacial drift that came from the Baltic region.