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. Geologists of the early 20 century thought a large trough, a so-called geosyncline, had existed between Scotland and England in the early Paleozoic, keeping both sides separated.