F S 



[ 181 ] 



FRO 



lines running in such directions as 

 to resemble a fortification, the 

 centre being often amethyst, with 

 jasper, quartz, &c., surrounding. 

 In composition it resembles other 

 agates ; it occurs in irregular nod- 

 ules, commonly in amygdaloid, as 

 in that of Scotland, called Scotch 

 pebble. 



FO'SSIL. | ffossiliSj from fodio, Lat. 



FO'SSILE. ) fossile, Fr. fossile, It.) 

 Dug out of the earth, as fossil 

 shells, fossil bones, fossil coal, &c. 

 The adjective is frequently spelt 

 fossile. 



FO'SSIL. A substance dug out of the 

 earth. At the present day, the 

 word fossil is used by geologists to 

 express only the remains of animal, 

 or vegetable, substances found buried 

 in the earth's crust. 



Fossil shells of forms such as 

 now abound in the sea, are met 

 with far inland, both near the sur- 

 face and at all depths below it, as 

 far as the miner can penetrate. 

 They occur at all heights above 

 the level of the ocean, having been 

 observed at an elevation of from 

 8,000 to 9,000 feet in the Alps and 

 Pyrenees, more than 13,000 feet 

 in the Andes, and above 15,000 

 feet in the Himalayas. Lyell. 



Mr. W. Smith was the first to 

 notice that certain fossils are pecu- 

 liar to, and are only found lodged 

 in, particular strata. The rapid ad- 

 vances made in geology have taught 

 the following facts respecting 

 fossils : that exactly similar fossils 

 are found in distant parts of the 

 same stratum, not only where it 

 traverses this island, but where it 

 appears again on the opposite coast; 

 that in strata of considerable com- 

 parative depth, fossils are found, 

 which are not discovered in any of 

 the superincumbent beds: that 

 some fossils, which abound in the 

 lower, are found in diminishing 

 numbers through several of the 

 superincumbent, and are entirely 



wanting in the uppermost strata : 

 that some fossils, occurring in con- 

 siderable numbers in one stratum, 

 become very rare in the adjacent 

 portion of the next superincumbent 

 stratum, and afterwards are lost: 

 that most of the remains which are 

 abundant in the superior strata, are 

 not at all found in the lower. 

 Geological Transactions. 



FRA'GMENTABY. Composed of frag- 

 ments. Dr. Johnson says, "a word 

 not elegant, nor in use : " in ele- 

 gance or euphony it may, or may 

 not, be deficient, but, at the 

 present day, it is in use by 

 geologists. 



FKANGIBI'LITY. (In mineralogy, one 

 of the physical characters of miner- 

 als.) Capability of being broken. 

 The degree of frangibility consists 

 in the ease with which a thing may 

 be broken. This quality varies 

 greatly in different substances, 

 ranging through all the interme- 

 diate degrees, from very brittle to 

 very tough. FrangibiUty, strictly 

 speaking, ought not to be considered 

 as connected with the ease or diffi- 

 culty with which minerals yield in 

 directions parallel to their natural 

 joints; it is rather applicable to 

 their property of yielding to me- 

 chanical force in other directions. 



FBEE-STONE. Any kind of stone, the 

 texture of which is so free or loose 

 that it may be easily worked. 



FB'ESHET. A flood or overflowing of 

 a river, by means of heavy rains or 

 melted snow ; an inundation of 

 fresh-water. Freshets take place, 

 more or less, in all rivers, greatly 

 augmenting their velocities and 

 transporting power, and carrying 

 forward substances that could not 

 have been moved under ordinary 

 circumstances.. 



FEOND. (from, Lat.) 



1. In botany, implies peculiar 

 union of the fructification with the 

 leaf and stem, namely, the flowerg 



