96 



REPORT — 1860. 



inferences ; Clionophi/Uum. perfolialum formed part of the Silurian and Devonian 

 faunas, but ,was confined to the British area; Pavo/tites Goldfussi was at home in 

 every part of the world, yet it commenced and terminated its career within the De- 

 vonian period. 



The rocks of Devon and Cornwall have 58 species of fossils in common with 

 those of the Carboniferous group*, but no corals or sponges amongst them ; so that 

 it cannot be said that " there is a blending of Silurian and Carboniferous corals in 

 Devonshire," whatever there may be elsewhere; for though, as has been stated, three 

 Silurian corals have been found, not one referable to the Carboniferous fauna has 

 been exhumed theref. 



The species which thus passed from the Devonian into the Carboniferous period are 

 found in the three principal fossiliferous deposits of Devon and Cornwall, as exhibited 

 in the following Table : — 



Table III. 



The populations of the three areas seem to have been thus composed : — 



South Devon ; — 6 Silurians + 220 new species (i. e. Lower Devonian)=a total of 

 226, of which 34 passed into the Carboniferous. 



Barnstaple : — 1 Silurian -f 13 Lower Devonians -f 64 new (Upper Devonians) = a 

 total of 78, of which 18 passed into the Carboniferous. 



Petherwin : — 1 Silurian -|- 15 Lower Devonians + 57 new (Upper Devonians) = a 

 total of 73, of which 18 passed over to the Carboniferous. 



Of the "new forms" in the Barnstaple and Petherwin areas (64 and 57 respect- 

 ively) 14 are common. 



It is perhaps worthy of remark that the five areas have a smaller number of organic 

 forms in common — closely connected as they are both in time and space — than with 

 Devonian deposits in Continental Europe and elsewhere beyond the British Isles, or 

 with the Carboniferous rocks of Ireland and Central and Northern England. 



Table I., to which attention has so frequently been directed, represents, so far as 

 is at present known, the absolute distribution of the fossils in the two counties in 

 which they occur ; but, for purposes of geological chronology, it is probably of greater 

 importance to ascertain their relative distribution; this is shown in Table IV., which 

 has been calculated from Table I. thus : the total number of species in each class is 

 put=1000, and the figures in the other columns equated to this. 



* See in Table I. the column headed " Carboniferous." 



t See ' Monograph of British Fossil Corals,' by Messrs. Edwards and Hainie, pp. 150 and 

 212. 



