CIIONETES. 17) 



possessing some of the characters of both P.plicatilis and P. mb-hevu, can always be dis- 

 tinguished by its narrow median ridge, deeper sinus, and lateral ribs. 



In England it is found in the Carboniferous limestone of Settle, in Yorkshire, the dark 

 limestone of Kendal, Poolwash, Isle of Man, as well as in the gray limestone of Derby- 

 shire. In Scotland it has been found at 375 fathoms below "Ell Coal." At Braidwood, 

 in Lanarkshire, also at Broekley, near Lesmahago; in Stirlingshire, in the Glarat lime 

 works, or Campsic main limestone. In Ireland at Cornaearrow, Millecent, Little Island. 

 On the Continent it occurs in the limestone of Vise and Tournay, in Belgium. In Russia, 

 at Ilinsk, on the Tchusovaya, Ural Mountains. 



Sub-genus — Chonetes, Fischer} 



We have already alluded to the close relationship which exists between Ciionetes and 

 Productus, and must now refer to the great difficulties in the way of a correct and definite 

 determination of its species, which appears to have been unnecessarily multiplied, and at 

 times been fabricated out of undeterminable or uncharacterised specimens or fragments. 

 The confusion in which I found the species was so great that all my many efforts, consul- 

 tations, and researches, have proved ineffectual to satisfactorily solve the difficulty with 

 reference to some few of Prof. M'Coy's Irish so-termed species ; but in order that the 

 reader may form his own opinion, or be better enabled to continue the research, I have 

 given figures of all the uncertain species (?), and, when desirable, reproduced the original 

 descriptions. I have not been able to determine satisfactorily more than five or six species, 

 viz. — 1. Chonetes comoides ,• 2. C. papilionaceaj 3. P. Dalntaniana ; 4. G. Sardrensis ; 

 5. C.Bucldana ; and 6. C. polita. Those termed C. laguessiana, De Kon., C. papgracea, 

 C. crassistria, C. tuber culata, C. sub-minima, C gibberula, C. sulcata, C.volva, C.perlata, 

 and C. serrata, M'Coy, may still demand further research, although I have myself but little 

 doubt that the whole number are merely different conditions or synonyms of some of the 

 five or six species above recorded ; and even out of this number I do not feel entirely confi- 

 dent with reference to C. Bahnaniana. In his monograph of the sub-genus Chonetes, 

 Prof, de Koninck states that " the slight difference which exists between the form and 

 the exterior sculpture of the various species renders their classification much more difficult 

 than that of Productus, and that he has taken as basis for his arrangement the number and 



1 Prof. M'Coy considers Chonetes to be simply a sub-genus of Leptoena, removing it, as well as 

 Strophalosia (King) and Aulosteyes (Helmersen), from tbe family Pkoductid.e (' British Pal. Foss., Cam- 

 bridge Museum,' p. 21 1), and placing them as a sub-genus among his Orthisidee ; but this view appears 

 to me far from correct, as I have endeavoured to demonstrate in p. 112 of my 'General Introduction,' when 

 showing that the reniform impressions are the same in Chonetes as in Productus, while a completely 

 different arrangement prevails among the Sirophomenidw, of which Leptoena constitutes only a section. 



