Complex sentence: Another study of fossil "A. cuneata" showed a large difference beween nearby (2 km) and almost contemporary (Middle Miocene, late Badenian) locations, 23% of the shells had holes at Weglin, bot only 2% at Weglinek.
Split into simpler sentences: Another study of fossil "A. cuneata" showed a large difference beween two nearby (2 km) and almost contemporary (Middle Miocene, late Badenian) locations. At Weglin, 23% of the shells had holes, but only 2% at Weglinek.