Simplify the following text for a Grade 10 native English-speaking person.
Original: At the start of the 20th century , American paleontologist Charles Walcott noticed differences in early Paleozoic benthic trilobites of Laurentia ( such as Olenellidae , the so called `` Pacific fauna '' ) , as found in Scotland and western Newfoundland and those of Baltica ( such as Paradoxididae , often called the `` Atlantic fauna '' ) , as found in the southern parts of the British Isles and eastern Newfoundland .
Simplified: The so called `` Pacific fauna '' of Laurentia , as found in Scotland and western Newfoundland , was quite different from those of Baltica , often called the `` Atlantic fauna '' . The latter is found in the southern parts of the British Isles and eastern Newfoundland .