TABLE A: SUBDIVISIONS OF '5 



55176 Secondary, Mesozoic. 



'55 l j6i Triassic. 



551762 Jurassic. 



'55177 Cretaceous. 



'55 1 ? 8 Tertiary, Neozoic. 



551781 Eocene. 



551782 Miocene. 



'55 I 7^3 Pliocene. 



55179 Quarternary. 



551791 Recent. 



5518 Structural geology. 



5519 Agents of geological work. 



552 Lithology. 



5521 Igneous rocks. 



5522 Volcanic. 



5523 Plutonic. 



5524 Metamorphic. 



5525 Aqueous. 



5526 Meteorites. 



5527 Decay of rocks. 



5528 Microscopical petrography. 



553 Economic geology. 



5531 Ore deposits. 



'5 S3 2 Carbon minerals. 



5533 Iron ores. 



'5534 Ores of other metals. 



'5535 Building stones. 



5536 Earths. 



5537 Mineral waters. 



5538 Gems. 



'5539 Other economic minerals. 



15 



