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Ammonites oxynotus, figures 2, 3, and 4, Plate 3, and which are 

 nothing more than the young of Gryphsea incurva, probably var. 

 obliqua. We have obtained large series of these at the brick-pits near 

 Lanthony Priory, Gloucester, and upon the canal banks between 

 Lanthony Bridge and the second mile post, the adult form being com- 

 paratively rare in the stratum. The shells figured as G. suilla by 

 Goldfuss, are also immature forms, no longer considered by most 

 Palffiontologists to be other than varieties of G. incurva, although 

 they seem to occur in such vast numbers, not advanced beyond 

 this stage of growth, in particular strata, as to form their charac- 

 teristic shells. Quenstedt, treating of the Malmstein of his Lias 

 Alpha, says significantly, with regard to the resemblances of this shell 

 to others, " Here, in the space between the worked stone, we meet for 

 the first time with distinct Gryphites which are very nearly allied to 

 arcuata, nevertheless, it is true, not yet with their doubled, crooked, 

 incurved beak upon them. Their precise determination is also rendered 

 diflicult, on account of their appearing for the most part as Casts. I 

 doubt not that G. arcuata proceeds from these, although they are smaller 

 and flatter." " Hehl allows them to continue under Zieten's name of 

 G. ovalis; others call them G. suillus of Schlotheim, because those from 

 the Haimberge, near Gottingen, are somewhat broader. G. obliquata of 

 Sowerby also, T. 112, f. 3, often agrees very well with them. "We 

 cannot arrive at a firm foundation with all such form-comparisons, since 

 they again differ amongst themselves in an extraordinary degree. , Here 

 stratigraphical position must assist us, or we proceed entirely in error." 

 (Page 54, Der Jura.) " He refers to Ostrea rugata, which occurs with 

 Ammonites angulatua, Httle wrinkled casts with crooked, strongly incurved 

 beaks, but which belong rather to the group of O. rugata," described by 

 him in the same work, at page 60. Zieten's figure of G. ovalis is here 

 usefiil for comparison, and Quenstedt, at page 46, suggests the same 

 between it and his O. rugata, a more thin and delicate shell, which appears 

 at a still earlier period. His O. irregularis and O. rugata are both referred 

 to his Ammonites psilinotus beds, — our Am. planorbis beds — the first, 

 described as a small, but fi-equently recurring oyster attached to Plagios- 

 toma and Monotis (avicula,) inaquivalvis, and growing upon them, but 

 upon separation quickly assuming the manner of growth of the Gryphites: 

 the second as occurring at •' Huttlingen, between the Malmstein and the 

 G. Arcuata beds, forming a thick bank, entirely filled with its thin wrinkled 

 shells," which forcibly call to mind G. arcuata, although the strata of 

 the Arietenkalk," (our A. Bucklandi beds) " are those in which this frilly 

 developed shell first appears." He nevertheless maintains that it is 

 traceable even lower than the Malmstein beds, we presume, in the form 



