

XXVI 



INTRODUCTION. 



iron-ore, hard earthy lead-ore, most blendes, white shining 

 cobalt-ore, native arsenic, kupfernikel, limestone, most cal- 

 careous spars and guhrs, fluor spar, zeolite, basalt, and many 

 others. 



" Soft solid fossils are those which are easily affected by 

 the knife, but receive no impression from the finger-nail. 

 Such are white silver-ore, vitreous silver-ore, most red silver- 

 ores, vitreous copper-ore, mountain blue-ore of copper, most 

 bog iron-ores (Rosen eisenstein), galena, compact lead-ore 

 (bkyschwelf) , white and green lead-ore, red phosphoric blende 

 (from Scharfenberg near Meissen), amber, heavy spar in bars 

 (Stangen spat), mica, asbestos, serpentine, &c. &c. 



" Very soft is applied to all solid fossils which are not only 

 marked by the knife, but upon which the finger-nail makes 

 an impression. Of this kind are most solid cinnabars, cor- 

 neated metals, or native metallic muriats, micaceous bismuth- 

 ore, grey ore of antimony, most earthy cobalt-ores, cobalt 

 flowers, oxyd of native arsenic, realgar, native sulphur, mi- 

 neral pitch, most pit-coal, plaster-stone, glades marice, talc, 

 black lead, most kinds of manganese, steatite ( Speck stein), 

 amianthus, chalk, &c. &c. 



" But these different degrees of hardness are so apt to ap- 

 proach each other, that we find each of them not only of 

 many varieties, but very frequently observe fossils bordering 

 upon two degrees of different hardness, which varying a little 

 from both, forms a medium between these two degrees. For 

 example, hard magnetic iron-stone and opal, have nearly the 

 same hardness with semi-hard kupfernikel and basalt ; semi- 

 hard copper pyrites and malachite approach the soft heavy 

 spar and white lead-ore in hardness ; soft red silver-ore and 

 amber approach the very soft cinnabar and native sulphur. 

 It becomes therefore a matter of importance to determine the 

 hardness of a fossil, to indicate not the principal degree of 

 hardness alone to which it belongs, but also its relation with 

 known fossils of the same degree, and to observe when a 

 fossil forms a medium between two degrees. Thus, for ex- 

 ample, we shall say that fahlers, or grey silver-ore, is semi- 





