551 - Geology, hydrology, meteorology 7,689
550 - Earth sciences 818
553 - Economic geology 766
552 - Petrology 645
555 - Earth sciences of Asia 128
556 - Earth sciences of Africa 68
557 - Earth sciences of North America 14
559 - Earth sciences of other areas 13
554 - Earth sciences of Europe 8
558 - Earth sciences of South America 6
541 - Physical chemistry 1
639 - Hunting, fishing & conservation 1