Complex sentence: Monteil and a small party of Frenchmen arrived in Dakar in September 1890, and went by railway up the coast to St. Louis, where he hired bearers and tirailleurs.
Split into simpler sentences: Monteil and a small party of Frenchmen arrived in Dakar in September 1890. He traveled by railway up the coast to St. Louis where he hired bearers and tirailleurs.