| OCR Text |
Show 60 SECONDARY FOSSIL SHELLS. y SHEILS COMMON TO THE MAESTRI CRT BEDS FOS!~n TH~ WHITE CHALK; COMMUNICATED BY M. DESHA YES. (See p. 325.) Catillus (Inoceramus) Cuvieri? (specimens i~perfect.) Plagiostoma spmos!'· Hopen. Peete~' fragilissimus. Ostrea vesteularis. , carinata. Crania Parisiensis. Ten:bratula octoplicata. " carnea. pumilus (magus, Sow.) , Defrancii. Bdemnites mucronatus. OSSIL SHELLS COMMON TO THE MAESTRICHT BEDS F AND THE UPPER GREEN -SAND; COMMUNICATED BY M. DESHAYES. (Seep. 325.) Plagiostoma spinosa. Ostrea vesicularis. ,, carinata. I Belemnites mucronatus. Baculites Faujasii. GLOSSARY Of Geological and other Scientific Terms used in this Work. Several of the Author's friend11, who had read tht! first and second volumes of the Principles of Geology, having met with difficulties from their previous un. acquaintance w!th the technical terms used in Geology nnd Natural IliMtory, suggested to h1m that a Glossary of those words would render his work much more accessibll' to general readers. The Author willingly compliecl with this suggestion, but finding that his own familiarity with the subject made him not a very competent juclgt~ of the tl!rms that rl!quired explanation, he· appli!!d to the fril!nclM above alluded to for their assistance, and from lists of words supplied by them, the following Glossary has bl!en constructed. It will be obvious to men of science, that in order to attain the object in view, it was necessary to employ illustrations and language as familiar as possible to the general reader. AcEPHALous. The Acephala are that division of molluscous animals which, like the oyster and scallop, are without heads. The class Acephala of Cuvier comprehends many genera of bivalve shells, and a few genera of mollusca which are devoid of shells. Etym., a, a, without, and ,;tq>aA.,,, cephale, the head. ALa..£. An order or division of the cryptogamic class of plants. The whole of the sea-weeds are comprehended under this division, and the application of the term in this work is to marine plants. Etym., Alga, sea-weed. ALuM-STONE, ALU:\fEN, ALUl\JINous. Alum is the base of pure clay, and strata of clay are often met with containing much iron-pyrites. 'Vhen the latter substance decomposes, sulphuric acid is produced, which unites with the aluminous earth of the clay to form sulphate of alumine, or common alum. Where manufactories are established for obtaining the alum, the indurated beds of clay employed are called Alum-stone. ALI.UVIAL. The adjective of alluvium, which see. ALLUVION. Synonymous with alluvium, which see. ALLUVIUM. Earth, sand, gravel, stones, and other transported matter wl1ich has been washed away and thrown down by rivers, floods, or otl1er causes, upon land not permanently submerged beneath the waters of lakes or seas. Etym., Alluo, to wash upon. For a further explanation of the term, as used in this work, see vol. ii. chap. xiv., and vol. iii. p. 145. |
