PENGELLY — FOSSILS OF DEVO^ AND COllNWALL. 



29 



Petherwin appears to have been riclier than Barnstaple in Zoo- 

 phyta and Cephalopoda, but poorer in Echinodermata and Lamelli- 

 branchiata; whilst neither of the areas has yielded any fossil 

 sponges. 



Assuming the higher antiquity of the South Devon and contempo- 

 rary beds — to which, probably, no geologist will object — it follows 

 that the fossils common to it and Petherwin, or Barnstaple, or both, 

 were contributions from it to them. Regarded thus, the populations 

 of the two areas were made up as is shown below. 



TABLE X. 





Pexhekwin. 



Baknstaple. 





Sp. 1 



Sp. 1 





„ 15 



„ 13 



New (peculiar) 



» 44 



„ 50 



New (common) 



„ 12 



13 





„ 13 



„ 16 



The term "peculiar," in the table, is meant to denote such species 

 as, in Eugland, are found in Petherwin or Barnstaple only ; and 

 "common" to mark those found in both, but not elsewhere in the 

 British Isles ; " carboniferous " is used to designate the species 

 common to the deposits of that age and Petherwin, or Barnstaple, or 

 both ; exclusive of six found also in Lower Devonian deposits. It 

 may be remarked here that no fossil occurring in South Devon, Pe- 

 therwin and Barnstaple, appears to have been found in Carboniferous 

 rocks. 



The Carboniferous figures 13 and 16 in Table X. are not in 

 addition to the previous numbers in the Table ; the totals — 72 and 

 76 respectively — are, of course, complete without them. 



In order to show the relative value of the figures just given, the 

 following Table has been calculated on the method of putting each 

 total 72 and 76 equal to 1000, and equating the other figures 

 in Table X. to it. It should be remembered, however, that whilst 

 this furnishes better data for comparison, it considerably magnifies 

 the facts. 



TABLE XI. 





Petherwik. 



Baenstaple. 





Sp. 14 



Sp. 13 





„ 208 



„ 171 



New (peculiar) 



„ 611 



„ 658 



New (common) 



„ 167 



„ 158 





181 



„ 231 



The Silurian figures are, of course, quite valueless further than as 



