OF FOSSILS. 173 



$ CXL. Enumeration of triple Species. 



EACH of the five letters in fortning triple 

 compofitions, may be arranged in twelve dif* 

 ferent ways. Five multiplied by twelve, there- 

 fore produce fixty fpecies as follows : 



pent, pea, pcf, pma, pmf t pmc, pa/I pac, pant, 



pfc, pfm, pfa. 

 cpm t epa, cpf, cmp, cma, tmf, cap, cam, caf, 



<fj>, cfm, cfa. 

 mpc, mpa, wpf, mcp, men, mcf, map, mac, maf t 



wfpi mfc % r??fa. 



ape, apm, apf, acp, acm, acf, amp, amc, amf, 



*$ nfc* fifm. 

 Jpc, fpm, fpa, fcp, fern, fca t frtp, fmc, firla, 



ex LI. Quadruple Species. 



As the double fpecies amount to twenty ; and 

 thefe, with the remaining three letters can be 

 combined in fix different ways, in the quadru- 

 ple fpecies, it will be eafily fcen, that fix times 

 twenty, or one hundred and twenty, will ex- 

 prefs the amount of this divifion 



S pcma, 



