T. Davidson — On Continental Geology. 203 



and their connection with the Mediterranean Basin (Bull. 2 series, 

 vol. XX., p. 575), and finally one on the insufficiency of the Ostrea 

 aquila as a medium to define the limits of a zone (Bull. 2 series, vol. 

 xxi., p. 351). In the fourth vol., 1 series, p. 291 of the Memoirs of 

 the G-eological Society of France, M. Leymerie classes the Lower 

 Cretaceous formation of the Department of the Aube in the following 

 manner : — 



Numbers Corresponding to the Same Beds in the Department of the 

 Haut-Makne as given by M. Oornuel, in his Section. 



^*Greef sand^^^' ^^^^ TeguHnes and rapper portion. 13 middle, & upper 14, 15, 16. 



(Etage des argiles tegulines et da j ^ower portion. 13 lower division. 

 gres vert). L ^ 



C r8, 9, 10, 11, and 12, (those 



I TT i. \ having been seen in the 



„ . , J Upper stage, -j pept. of Aube, in kidney- 



Neocomien stage. ^ (_ shaped masses only). 



Middle stage. 7. 



(^ Lower stage. 1, 2, 3, 4, and 5. 



In his history of the progress of Geology, vol. iv. p. 278, Vicomte 

 d'Archiac suggests the following distribution : — 



f TT i. ( Upper beds No. 14, 15. 



^^ . ^ Upper stage. | Lower bed 13. 



Neocomien Group, I f Upper beds 8, 9, 10. 11, 12 P 



o^'of „ ^ ^i*^*^^^ ^*'^^®- ) Lower bed 7. 



the Lower Green Sand. I ^ tt„.,^,. ^^^c k 



T J. f Upper beds 5 and 6. 



t ^°^^^ "*^^^- 1 Lower beds 1, 2, 3, 4. 



M. Eenevier thinks that the relations with the Perte-du-Khone 



are as follows (Bull. Soc. Geol. France, 2nd. series, vol. xii., p. 89, 



and vol. xi., p. 114). 



Gault No. 15-16. 



Aptien „ 13,14. 



Rhodanien... „ 12. 



Urgonien „ 10,11. 



(8 and 9 are left without reference to what precedes 

 or follows). 

 Stage of Hauterive or ") k a n 

 Middle Neocomien 5 t>. «>. /• 



(3 and 4 are left without reference to what precedes 

 or follows). 

 V^angien or Lower ^ i and 2. 

 Neocomien ) 



Lastly, in vol. xxiv., p. 379, 1867, of the Bulletin Soc. Geol. 



France, M. Hebert establishes the correlations between the series of 



the Haute-Marne and Southern France, Switzerland and Spain, and 



for which he proposes the following scheme, but from which he, M. 



Cornuel, dissents : — • 



["Upper sub-stage (Aptien of d'Orbigny), No. 13 of the Haute-Marne. 

 I Middle sub-stage, f upper beds, „ 12, 



8, 9, 10. 11 

 17, „ 

 5,6, „ 

 1, 2, 3, and 4 



XT • j (Urgonien d'Orb.), Mower beds, 



Neocomien. <^ ^ ^ f upper bed, 



j Lower sub-stage, ■< middle bed, 

 (^ (.lower bed, 



These different schemes and the corresponding numbers furnished 

 to me by M. Cornuel, at once show the views entertained by the 

 above-named geologists at the period of their various communications. 



