Complex sentence: He published his first scientific paper in 1849, on fossil fish found in East Cornwall, the first of over 100 such papers on geology, paleontology and human prehistory that he published in his lifetime.
Split into simpler sentences: He published his first scientific paper in 1849, on fossil fish found in East Cornwall. This was the first of some 120 papers on geology, paleontology and human prehistory that he published in his lifetime.