West Thailand in the Ordovician world (4 fig., 2 Tab.) Trilobita from the Kanchanaburi Region (Arenig) and from the Thong Pha Phum Region, Middle to Late Ordovician (23 fig., 3 tab., 4 plates) Ostracoda from Thong Pha Phum and Bo Noi Regions, West Thailand (15 fig., 4 tables, 4 plates) Cystoidea and Crinoidea from the Thong Pha Phum Region, Middle to Early Late Ordovician (12 fig., 1 tab., 6 plates).