GLOSSARY. 77 



in which the reproductive organs are apparent. Etym. ^avepoc, 

 phaneros, evident, and ya/zoe, gamos, marriage. 



PHYSICS. The department of science, which treats of the properties 

 of natural bodies, laws of motion, &c., sometimes called Natural 

 philosophy and mechanical philosophy. Etym. tyvgtg, physis, 

 nature. 



PHYTOLOGY, PHYTOLOGICAL. The department of science which relates 

 to plants synonymous with botany and botanical. Etym. 

 0vrov, phyton, plant, and Xoyoc, logos, discourse. 



PHYTOPHAGOUS. Plant eating. Etym. QVTOV, phyton, plant, and 

 (fxtyetv, phagein, to eat. 



PISLIAR, a misprint for PISTIA, in vol. ii. p. 98, 1st ed., p. 102, 2cl 

 ed. The plant mentioned by Malte-Brun is probably the Pistia 

 stratiotes, a floating plant, related to English duck-weed, but 

 very much larger. 



PISOLITE. A stone possessing a structure like an agglutination of 

 pease. Etym. niaov, pison, pea, and Xi0oe, lithos, stone. 



PIT COAL. Ordinary coal ; called so because it is obtained by sink- 

 ing pits in the ground. 



PITCH STONE. A rock of an uniform texture, belonging to the un- 

 stratified and volcanic classes, which has an unctuous appear- 

 ance, like indurated pitch. 



PLASTIC CLAY. One of the beds of the Eocene tertiary period (see 

 Table II. E, p. 390.) It is so called because it is used for 

 making pottery. Etym. TrXao-crw, plasso, to form or fashion. 



PLESIOSAURUS. A fossil extinct amphibious animal, resembling the 

 saurian, or lizard and crocodile tribe. Etym. irXriffiov, plesion, 

 near to, and crai/pa, saura, a lizard. 



PLIOCENE. See explanation of this term, vol. iii. p. 53. 



PLUTONIC ROCKS. For an explanation of this term, see vol. iii. 

 p. 353. 



POLYPARIA. CORALS. A numerous class of invertebrated animals, be- 

 longing to the great division called Radiata. 



PORPHYRY. An unstratified or igneous rock. The term is as old 

 as Pliny, and was applied to a red rock with small angular 

 white bodies diffused through it, which are crystallized felspar, 

 brought from Egypt. The term is hence applied to every spe- 

 cies of unstratified rock, in which detached crystals of felspar 

 are diffused through a base of other mineral composition. 

 Etym. 7rop</>vpa, porphyra, purple. 



PORTLAND LIMESTONE, PORTLAND BEDS. A series of limestone strata, 

 belonging to the upper part of the Oolite group (see Table II. 



