4 INFERIOR OOLITE AMMONITES. 



upper portion of these sands being equivalent to the Pisolite and the lower portion 

 to the sands and marls of the Upper Lias which occur in Gloucestershire. I shall 

 give some further opinions on this view presently. 



In reading the descriptions of Brachiopoda by M. E. Deslongschamps, 

 1862, we find that he places between the Oolite and the Lias certain beds 

 which he calls Infra-Oolitic marls. In these Infra-Oolitic marls he places the 

 Opalinum-, Murchisonge-, and Sowerbyi-zones (see pages 213, 209, &c. ), and he 

 would seem to wish to begin the Inferior Oolite proper with the zone of 

 Am. Sauzei. Mr. Hudleston once suggested the proposal of two large divisions 

 for the Inferior Oolite, the one called the Harpoceras-zone to end with the 

 Sowerbyi-bed, because Ammonites belonging to the division Harpoceras are the 

 characteristic fossils, the other to contain the Sauzei-, Humphriesianum-, and 

 Parkinsoni-zones and to be called the Stephanoceras-zone, or probably I would 

 rather suggest, Stephanoceratites-zone. This, however, is a digression, and does 

 not help us to determine the lowest zone of the Inferior Oolite, except that it 

 shows how a division could be made. Deslongschamps has recognised this, and 

 proposed to make as it were a small intermediate formation, as if to combine 

 the various views of different authors, under the name Infra-Oolitic marls. It must, 

 however, be noticed that he ends the Lias with the Jurense-zone. 



Dr. Wright, in his ' Monograph on the Lias Ammonites,' at page 148 (Palasonto- 

 graphical Society, vol. xxxiii, 1879) brings in the Opalinum-zone as the highest 

 zone of the Lias ; and after describing where it occurs and its characteristics, he 

 says, " From the Haresfield bed I have taken a piece of rock having the impres- 

 sion of Harpoceras opalinum on its underside, whilst the block itself contained 

 Inferior Oolite fossils." These words to my mind do not point to any great 

 advantage in making the division between Lias and Oolite at a point where the 

 zones are so intimately connected, unless the majority of authors express a prefer- 

 ence for this as the distinguishing point. At the same time it could probably be 

 urged that wherever the distinction were drawn some locality or other would 

 present this difficulty. Dr. Wright has, however, so far carried out his opinion 

 that he has figured and described in his Monograph a number of Ammonites from 

 the Opalinum-zone. Consequently, even if it be determined, that it is advantageous 

 that the Opalinum-zone should belong to the Inferior Oolite, I should find part 

 of my work done by Dr. Wright. It is not improbable, however, that wherever 

 the division between Lias and Oolite may be drawn, I may have some species 

 to describe from the Opalinum-, and perhaps Jurense-zone, so as to be able to 

 connect Dr. Wright's splendid ' Monograph on the Lias Ammonites ' with the 

 present work without any break. 



Dr. Branco, in ' Der Untere Dogger Deutsch-Lothringens ' (page 14), begins 

 his description of the Dogger as follows : — " (1) Die Schichten mit Harpoceras 



