298 Mints for a Theory of the Earth. 



3. To determine the refpective antiquity of the genera and 

 fpecies of the earths and ftones which enter into the com- 

 petition of fecondarv mountains. Might we not affign cha- 

 racters by which, in the fame genus, we might diftmguilh 

 the moft modern fpecies and varieties ? 



4. Whether the fecondarv mountains are always inclined 

 in fuch a manner as to lean towards the neareft primitives i 



5. Whether their fuperior ftratum, efpecially in the com- 

 pact calcareous, is not often a brecbe* 3 the angular frag- 

 ments of which are for the moil part of the fame nature as 

 the ftratum that fcrves them as a bafis, and united by a 

 cement of the fame nature t ? 



5. (A). To obferve in the chalk mountains the flints con- 

 tained there; their bulk, their form, Sec.; whether .they 

 nre dilpofcd in beds; to reficel on their origin: even re- 

 fearches on the petro-ijlex contained in the compact cal- 

 careous ftones; and, lalily, (lie fame on the hard rognons i or 

 touch-ftones contained in the (late mountains: to afcertaiu 

 whether thefe petro-filex and rognong arc not found in the 

 primitive mountains, 



6. Whether there are found in fecondarv mountains vef- 

 tiges of organifed bodies, and at what elevation. This obfer- 

 vation is important above all in the Auftral hemifpheret. 



7. Whether there are found, either at their furface, or in 

 their interior parts, rolled pebbles or blocks of a nature dif- 

 ferent from that of the fame mountain, and to what height |j ? 



S. Whether thefe mountains fecm to have been formed 

 by the alluvion of violent tides, or by the accumulated de- 

 posits of ftagnant water ? 



9. Whether the fecondarv mountains do not prefent them- 



* Breche is a kind of h:.rd marble found in the Pyrenees. 

 -r Voyage dans les Alpes, vol. i. § 242. A and 245. 

 1 (>. A. Do not organifed bodies contribute (orr-ttiir.es to the hardncS 

 •of ftones, efpecially thofe that contain iron, bv bringing that iron near to 

 the metallic ftate ? Hxpothefis of Gad in Man. of the. Acad, of Sv 

 c 

 [) See Dolomicu'i Memoir Journal do Phyfique 1791, vol. ii. 



ftl\vJ 



