500

Natural Sciences and Mathematics

550

Earth Sciences

501

Philosophy and theory

551

Geology, hydrology, meteorology

502

Miscellany

552

Petrology

503

Dictionaries and encyclopedias

553

Economic geology

504

554

Earth sciences of Europe

505

Serial publications

555

Earth sciences of Asia

506

Organizations and management

556

Earth sciences of Africa

507

Education, research, related topics

557

Earth sciences of North America

508

Natural history

558

Earth sciences of South America

509

Historical, areas, persons treatment

559

Earth sciences of other areas

510

Mathematics

560

Paleontology, Pale zoology

511

General principles

561

Paleobotany

512

Algebra and number theory

562

Fossil invertebrates

513

Arithmetic

563

Fossil primitive phyla

514

Topology

564

Fossil Mollusca and Molluscoidea

515

Analysis

565

Other fossil invertebrates

516

Geometry

566

Fossil Vertebrata (Fossil Craniata)

517

567

Fossil cold-blooded vertebrates

518

568

Fossil Aves (Fossil birds)

519

Probabilities and applied mathematics

569

Fossil Mammalia

520

Astronomy and Allied Sciences

570

Life Sciences

521

Celestial mechanics

571

522

Techniques, equipment, materials

572

Human races

523

Specific celestial bodies and phenomena

573

Physical anthropology

524

574

Biology

525

Earth (Astronomical geography)

575

Evolution and genetics

526

Mathematical geography

576

Microbiology

527

Celestial navigation

577

General nature of life

528

Ephemerides

578

Microscopy in biology

529

Chronology

579

Collection and preservation

530

Physics

580

Botanical Sciences

531

Classical mechanics, solid mechanics

581

Botany

532

Fluid mechanics, liquid mechanics

582

Spermatophyta (Seed-bearing plants)

533

Gas mechanics

583

Dicotyledones

534

Sound and related vibrations

584

Monocotyledones

535

Light and paraphotic phenomena

585

Gymnospermae (Pinophyta)

536

Heat

586

Cryptogamia (Seedless plants)

537

Electricity and electronics

587

Pteridophyta (Vascular cryptogams)

538

Magnetism

588

Bryophyta

539

Modern physics

589

Thallobionta and Prokaryotae

540

Chemistry and Allied Sciences

590

Zoological Sciences

541

Physical and theoretical chemistry

591

Zoology

542

Techniques, equipment, materials

592

Invertebrates

543

Analytical chemistry

593

Protozoa, Echinodermata, related phyla

544

Qualitative analysis

594

Mollusca and Molluscoidea

545

Quantitative analysis

595

Other invertebrates

546

Inorganic chemistry

596

Vertebrata (Craniata, Vertebrates)

547

Organic chemistry

597

Cold-blooded vertebrates, fishes

548

Crystallography

598

Aves (Birds)

549

Mineralogy

599

Mammalia (Mammals)