256 M. Desnoyers on the Chalk of the Cotentin. 



that it existed prior to the calcaire grossiei- and its marls. 

 Every where, in fact, where the bacuUte hmestone is covered, 

 at least to my knowledge, it is evidently so by one of the beds 

 of this latter formation, especially by the concretionary lime- 

 stone. 



When, as with certain marls, the contact with the calcaire 

 grossier occurs as a leaning against leather than as a real su- 

 perposition (as at Freville, Orglandes, and Bonne Ville), no 

 traces can be observed of its passage beneath the beds of the 

 compact chalk ; while strong proofs of the contrary are found 

 in the real position of one of these maris above the baculite 

 limestone of Sainte Colombe, in the absence of any kind of 

 bed above the calcaire grossier which might represent the ba- 

 culite limestone, and in the absence in the midst of the latter 

 of every organic or mineral remain which could have belonged 

 to the former. A still stronger proof would be afforded by 

 the dip of the baculite limestone beneath the Jahhms of the cal- 

 caire grossier, which I consider I have observed at Orglandes ; 

 yet however, too imperfectly to be given as a positive fact. 



I shall not further insist on these mutual relations, which ex- 

 amples of real stratification will make more clear, by showing 

 the direct position of the chalk beneath the calcaire grossier. 



c3 



SU jj 



ta' 



q2 



Section of the principal Baculite Limestone Qxiany at Fre- 

 ville. 



f~ 1. Vegetable earth. 



2. Rolled debris of quartz, white sandstone, and 

 chert ; fragments of corroded and worn millio- 

 lite limestone; enveloped in a brown sandy clay. 



3. Concretionary pisolite limestone, either imbed- 

 ding these debris, or more homogeneous, di- 

 vided into plates of three or four inches. 



4. Pale chert, surrounded by a chalky substance. 



5. Incoherent limestone, slightly marly, containing 

 many small corals, thecidea?, craniae, and 

 nucleolites. [1st fahlun). 



6. Hard and compact baculite limestone. 



7. Calcareous marl, nearly friable, [fahlun). 



8. A slightly cellular bed of compact limestone. 



9. Neai'ly powdery and incoherent bed. 



10. An irregularly indurated bed. 



11. Very continuous bed, the most compact of the 

 whole quarry. 



The same fossils in all the beds. 



2. Qjiarri^ 



