508 



J. F. BLAKE ON THE UPPER 



rocks so far has no difficulty in assigning to their true place the 

 magnificent limestones which here astonish him and give him an 

 idea of the grandeur of the development of the Corallian rocks in this 

 district. The beds which in this locality overlie the Ferruginous 

 Oolite are altogether different from any thing seen before, consisting 

 at Haudainville of an unstratified mass of limestone 40 feet in thick- 

 ness, made almost entirely of fragments of crinoids united by a cal- 

 careous cement and yet distinct, forming a most admirable freestone : 

 the only fossils seen in it are Cidaris florigemma and small oysters. 

 Capping this mass in the quarry is 10 or 12 feet of Thamnastrsean 

 Rag with occasional Cladophyllice, but with abundance of Cidaris 

 florigemma, Terebratula maltonensis, and Pecten vimineus, also Lima 

 Iceviuscula and Venerupis corallensis. The position, then, in this 

 locality of the crinoid limestone is fixed ; for it must be associated 

 with the Rag above it, as forming part of Buvignier's Coral Rag b. 

 The succeeding rocks, representing the Novion limestones, also intro- 

 duce new features ; for here is first seen the lithographic stone which 

 becomes so abundant further west. It is mixed with Oolites of 

 various-sized grains ; but the corals of all kinds are gone. The ap- 

 pearance of this group in the great quarries of St. Martin has been 

 admirably described by Buvignier — its cherty bands, its vegetable 

 remains towards the base, and crustaceans above. The fossils are 

 only abundant in parts; the commonest is Nerincea elongata, associated 

 with others, as iV. Jollyana and Patella elegans ; Natica globosa and 

 Lvcina mosensis were also collected. The upper part of this group 

 is instructively seen on the north of Verdun, in the Cote St. Michel. 

 The eastern portion is worked in pure lithographic limestone without 

 a fossil; but the western shows great quarries of massive earthy lime- 

 stones in which the characteristic fossil is Terebratula repeliniana, 

 d'Orb., as at Novion, but which shows its relation to the overlying 

 rocks by its numerous Astarte supracorallina , &c. The long lists of 

 fossils given by Buvignier as coming from his two divisions of the 

 Coral Rag, of which the present is his a, contain many species in 

 common, especially Diceras arietinum ; nevertheless there can be little 

 doubt of their corresponding with beds showing more distinctness 

 further north. We find therefore the same subdivision of rocks, here 

 referred to the Corallian, as in the Ardennes, namely a variable mass of 

 coral-bearing or crinoidal limestone below, with Cidaris Jlorigemma, 

 and a more compact and oolitic stone above, with many Nerinwce, 

 and an occasional Diceras. Hebert (21) thinks to divide the lower 

 part into two portions, the base a shell-bed with Cidaris florigemma 

 and the corals above ; but the extreme variability of these rocks, and 

 the occurrence of the characteristic urchin throughout all the modi- 

 fications, render such a division valueless. 



In this neighbourhood the first examination of the higher" beds 

 has been made along the road leading from Yerdun westwards to 

 Clermont-en-Argonne. Leaving the town by the fort on the north- 

 west, one's position is accurately determined by observing the great 

 coral-reefs on which the foundations are built, associated with the 

 gasteropod-bearing intercoralline brash, followed in the railway- cut- 



