SCO 



396 ] 



SEC 



SCOEIA'CEOTTS. Kesembling scoria ; 

 containing scoria. 



SCO'EIOTIS. Drossy ; cindery ; excre- 

 mentitious. 



SCORPION". (ffKopTrios, Gr.) A genus 

 of arachnidans, belonging to the 

 family Pedipalpi, order Pulmonarise. 

 The scorpion is remarkable, not 

 only for the powerful organs by 

 the aid of which it is able to seize 

 its prey, but also for its jointed 

 tail, terminating in a deadly sting. 

 The palpi are very large, with a 

 forceps at the extremity resembling 

 a hand ; the tail is composed of 

 six joints, the last joint terminating 

 in an arcuated and exceedingly 

 acute point or sting, which allow 

 the exit of a poisonous fluid, con- 

 tained in an internal reservoir. 

 The scorpion is provided, on each 

 side of the thorax, with four pul- 

 monary cavities, into each of which 

 air is admitted by a separate exter- 

 nal opening. The eyes are com- 

 pound, accompanied by stemmata. 

 A fossil scorpion has been dis- 

 covered by Count Sternberg in the 

 ancient coal formation at Chomle, 

 near Kadnitz. 



SCEEW STONE. The name of a fossil 

 resembling, at first sight, a screw ; 

 if, however, the marks be care- 

 fully examined they will be found 

 to be circular, and not spiral. 



SCEOBI'CULATED. (scroliculus, from 

 scrols, a furrow, Lat.) Furrowed ; 

 having small ridges and furrows. 



SCETJ'BSTONE. A provincial term for 

 a species of calciferous sandstone. 



SCY'PHIA. A genus of zoophytes. 

 Fossil scyphise occur in the oolitic 

 and cretaceous groups. In the 

 oolitic, forty one species have been 

 determined by Goldfuss and Mun- 

 ster ; in the cretaceous" group 

 twelve species have been deter- 

 mined by Goldfuss. Five species 

 are mentioned as having been found 

 in the grauwacke. 



SEAM. A term used to designate a 

 thin stratum ; as a seam of coal. 



SCTJ'TTJM. (scutum, Lat. a shield or 

 buckler.) A species of Echinite. 

 The name given by Klein to the 

 third section of the class Catocysti ; 

 the scutum of Klein is the Echin- 

 anthus of Leske. 



SEA PEN. A purple-coloured zoophyte. 

 SE'CONDAEY FOEMA'TION. \ By se- 

 SE'CONDAEY STEATA. > condary 



SE'CONDAEY EOCKS. ) rocks are 



meant those stratified rocks older 

 than the tertiary, which contain 

 certain distinct organic remains, 

 and are now commonly called Meso- 

 zoic. The principal groups of the 

 secondary formations are as follows : 

 1. The cretaceous group, begin- 

 ning with the Maestricht beds, and 

 terminating in the lower greensand. 

 2. The Wealden group, commen- 

 cing with the Weald clay, and 

 closing with the Purbeck beds. 3. 

 The oolite, or Jura limestone group, 

 beginning with the Portland beds, 

 and ending with the inferior oolite. 

 4. The lias group. 5. The new 

 red sandstone group, commencing 

 with the Keuper and ending in the 

 red conglomerate. 6. The carbon- 

 iferous group, comprising the coal 

 measures, the mountain limestone, 

 and the old red sandstone. 7. The 

 graywacke group. 



The secondary strata cover a 

 large portion of the habitable globe, 

 and are the immediate subsoil of 

 the most fertile districts of Europe. 

 The secondary strata are composed 

 of extensive beds of sand and sand- 

 stone, mixed occasionally with 

 pebbles, and alternating with de- 

 posits of clay, marl, and lime- 

 stone. The materials of most of 

 these strata appear to have been 

 derived from the detritus of primary 

 and transition rocks; and the 

 larger fragments, which are pre- 

 served in the form of pebbles, 

 often indicate the sources from 

 which these rounded fragments 

 were supplied. Six substances are 

 interstratified in this system : aron- 



