246 PROCEEDINGS OF THE GEOLOGICAL, SOCIETY. 



tsnv •''Mi Note by D. Sharpe, Esq., F.G.S. I\ae' ,7,t'Hf;>o8 



My DEAR Sir, — lu compliauce with your request, I Mvfe'drawfi 

 up a list of the palseozoic fossils which we collected in the Boulonnais 

 (see Tabular List), adding such other species (with an asterisk 

 attached) as are recorded in the accompanying list, p. 250. A review of 

 the organic remains in these beds will lead to some interesting results. 



The two great bands of carboniferous limestone of the Carrieres 

 Napoleon and of the Havit Banc must be classed from their fossils in 

 the vipper and middle divisions of the Carboniferous Limestone forma- 

 tion, corresponding with the limestones of Bristol and Derbyshire, 

 with those of Yorkshire (Avith the exception of the lowest beds), 

 and with that of Vise in Belgivmi. The presence of coal between 

 these two beds of marine limestone is analogous to what Mr. Phillips 

 long ago described in Yorkshire. Coal-beds of a similar age are also 

 found in Coalbrook-dale and in the Lothians, but the upper limestones 

 of those localities are mostly of freshwater origin. 



The shales below the Haut Banc limestone have not yet supplied 

 any organic remains ; but the beds of yellow sandstone on which they 

 rest are interesting to us, as they contain the species of CucuUeea 

 which abound in the sandstone of Marwood, in North Devon, and 

 thus fix the place of that bed in the geological series, which was 

 previously somewhat obscure. 



All the beds which crop out on the surface from below the yellow 

 sandstone belong to one formation, and contain nearly the same 

 species of organic remains ; the Ferques limestone is the most im- 

 portant of these, and is the most exposed to observation ; it has in 

 consequence yielded the richest harvest to the palaeontologist*. These 

 beds have hitherto been classed in the Devonian series, but if that 

 view be correct, there can be in this district no representative of the 

 Tournay limestone or lower division of the Carboniferous Limestone 

 series, and the middle diA^sion of that series must here rest con- 

 formably on the top of the Devonian formation. 



The Ferques limestones have been called Devonian, on the principle 

 that the Devonian system includes all the beds between the Carboni- 

 ferous Limestone and the Silurian rocks ; but the base-line of the 

 Carboniferous Limestone has been drawn upon different principles in 

 different districts, so that beds which ought to be classed together as 

 of one age are called Carhoniferous in Ireland and Northumberland, 

 and Devonian in Devonshire and the Boulonnais. On the other 

 hand, the Devonian system has been made to include beds as well 

 distinguished by organic remains as the upper Silurian formation is 

 from the lower f. It is high time for us to follow the good example 



* M. de Verneuil ; BuU. Soc. Geol. Fr. vol. ix. p. 388, 1838. ij-J jiU 



Sir R. I. Murchison ; vol. xi. of the same, p. 240, 1840. , qofijif^tJ 



Mr. Lonsdale ; Trans. Soc. Geol. 2 ser. vol. v. p. 736, 1840. ," -^ 



Visct. d'Arcliiac and M. de Verneuil, ib. vol. vi. p. 380, 1841. 

 MM. Milne-Edwards & Haime, Archives du Museum, vol. v. 

 t At the late meeting of the British Association at Belfast, the inconsistency of 

 the line of separation betvi^een the Devonian and Carboniferous formations of the 

 north and south of Ireland was pointed out by Mr. Jukes. See Literary Gazette 

 of 25th Sept. 1852. 



