CONTENTS. XV 



433. Argnio-calcareou?, or true marl, 433. Shell-sand, 434. Shell marl, as understood in 

 Britain, 434-5. Tertiary fossil shell marl (in Virginia), 435-6. Miocene marl, 437 to 440. 

 Varieties, 441 to 448. Crystallization in marl, 443-4. Loss of calcareous parts of marl, 448. 

 Comparative values, 449. Eocene marl, 450 ; of Coggins Point, 450-1. Extent of same kind, 

 452. Qualities, 453. Other eocene marls, 454. Gypseous earth, 454. Gypseous earth of Jamca 

 river, 455 to 475. Green-sand, 458. Use of gypseous earth as manure, 459. Sulphurct of iron 

 (and gypsum) contained, 460. The various strata at Evergreen, 462 to 464. At Coggins 

 Point, 465 to 467. Harrison's Bar of gypseous earth, 467. Green-sand of New Jersey, 468. 

 Analyses of green-sands of Europe and America, 469-70. Analyses of gypseous earth of 

 Coggins Point, 471 to 473. Gypsum the main operating ingredient, 474. Eocene green- 

 sand (or gypseous) marl of Pamunkey, 475 to 482. Different layers described, 476 to 479. 

 Olive earth, 479-80. Gypseous earth of Pamunkey, 481-2. All appreciable effects due, not 

 to green-sand, but to gypsum, 482. Position and order of succession of the different layers 

 of the Pamunkey eocene, 483 to 485. Suiphuret of iron in gypseous earth and some marls, 

 486-7. Alleged existence of green-sand, in quantity, in ordinary miocene marls, 487-8. 

 The assertion disproved, 489 to 491. Peculiar miocene. of Hampstead bed only, known to 

 contain green-sand in considerable proportion, 491 to 493. 



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