78 GLOSSARY. 



IF, p. 391.), found cliiefly in England, in the Island of Portland 

 on the coast of Dorsetshire. The great supply of the building 

 stone used in London is from these quarries. 



POZZUOLANA. Volcanic ashes, largely used as mortar for buildings, 

 similar in nature to what is called in this country Roman cement. 

 It gets its name from Pozzuoli, a town in the bay of Naples, 

 from which it is shipped in large quantities to all parts of the 

 Mediterranean. 



PRODUCTS. An extinct genus of fossil bivalve shells, occurring only 

 in the older of the secondary rocks. It is closely allied to the 

 living genus Terebratula. 



PUBESCENCE. The soft hairy down on insects. Etym., pubesco, 

 the first growth of the beard. 



PUMICE. A light spongy lava, of a white colour, produced by gases, 

 or watery vapour getting access to the particular kind of glassy 

 lava called obsidian, when in a state of fusion it maybe called 

 the froth of melted volcanic glass. The word comes from the 

 Latin name of the stone, piime.x. 



PURBECK LIMESTONE, PURBECK BEDS. Limestone strata belonging 

 to the Wealden group. See Table II. G, p. 390. 



PYRITES (Iron). A compound of sulphur and iron, found usually in 

 yellow shining crystals like brass, and in almost every rock 

 stratified and unstratified. The shining metallic bodies, so often 

 seen in common roofing slate, are a familiar example of the 

 mineral. The word is Greek, and comes from TTV/), pyr, fire, 

 because, under particular circumstances, the stone produces 

 spontaneous heat and even inflammation. 



QUADRUMANA. The order of mammiferous animals to which apes 

 belong. Etyin., quadrus, a derivation of the Latin word for 

 the number four, and mamis, hand, the four feet of those 

 animals being in some degree usable as hands. 



QUA-QUA-VERSAL DIP. The dip of beds to all points of the com- 

 pass around a centre, as in the case of beds of lava round 

 the crater of a volcano. Etym., qua-qua verswn, on every 

 side. 



QUARTZ. A German provincial term, universally adopted in scientific 

 language, for a simple mineral composed of pure silex, or earth 

 of flints ; rock-crystal is an example. 



RED MARL. A term often applied to the New Red Sandstone, which 



