570 Notices of Memoirs — Dr. T. Wright : — 



A. rotiformis. These are equivalent to the other Lower Lias zones, 

 those of A. Bucklandi, A. Turneri, A. obtusus, A. oxynotus, and A. 

 raricostatus. 



The Liasien, which attains a considerable development at Semur, 

 represents our Middle Lias, and the Toarcien, which attains nearly 

 600 feet, our Upper Lias. The " Upper Lias Sands " appear to be 

 represented in the Cote-d'Or by ferruginous limestones and clays ; 

 they are included in the Toarcien. In the Cotteswolds, where they 

 consist of sand and calcareous sandstones, and the distinction is 

 sufficient to give a separate name to them, there is a diversity of 

 opinion as to whether they are more closely related to the Upper 

 Lias clay or to the Inferior Oolite. The probability seems that, in 

 this respect, they occupy much the same position as the Ehaetic beds, 

 which belong as much to the Trias as to the Lias, and that similarly 

 the sands form a passage between the Upper Lias clays and the lime- 

 stones of the Inferior Oolite. The name should therefore be of a less 

 particular kind, and have reference rather to any peculiar features of 

 the beds themselves, or to the locality where they are best exhibited. 



3. Inferior Oolite. — The Ooliihe Inferieure (or E'tage Baj'ocien) 

 is well developed in the departments of the Cote-d'Or, Saone-et- 

 Loire, and the Ehone, and it will bear, in many respects, the same 

 divisions which this stage presents in the Cotteswold Hills. M. de 

 Ferry has well described the Inferior Oolite of the neighbourhood of 

 Macon, and Dr. Wright here reproduces a generalized section of the 

 beds in the Jvira Maconnais, in order to show how well the structure 

 of our English Oolite is repeated in the centre of France. The Cote- 

 d'Or presents a section essentially the same. It is divided by M. 

 Martin into five stages. 



4. Great Oolite Gtroup. — In the C6te-d 'Or, according to M. 

 Martin, the Bathonien stage exhibits six paleeontological zones, all 

 perfectly distinct, and which represent, as Dr. Wright shows, the 

 beds from the Fuller's Earth to the Cornbrash, inclusive. Dr. Wright 

 gives a detailed description of the beds which occur in the West of 

 England. The identification of this great Oolite group is essentially 

 palseontological . 



The Northampton sands, until lately considered to represent the 

 Stonesfield slate (Great Oolite), are now referred, on palseontological 

 grounds, to the Inferior Oolite. Between the Great Oolite and the 

 Forest Marble there sometimes occurs a bed called the Bradford 

 clay. Although considered as merely a local thickening of a Forest 

 Marble-clay, Dr. Wright remarks that when this is wanting, it is 

 almost impossible to distinguish the upper beds of the Great Oolite 

 from those of the next formation. 



5. Oxford Clat. — The Oxford clay, or Oxfordien, of the Cote- 

 d'Or, is divided into five stages. The lowest, a very fossiliferous 

 stage, represents the Kelloway rock. The other stages consist in the 

 main of marls, in which the lower calcareous grit appears to be 

 represented. 



6. Coralline Oolite. — Ammonites, so useful in the other Jurassic 

 formations, being rare in the Corallian strata, other leading fossils 



