86 



preservation, both in the limestone layers and in the clays. Figures 3 

 and 4 may appear of greater width than usual in proportion to their 

 length, but if studied in the inexhaustible series always to be found 

 in the locality indicated, the observer may speedily convince himself, 

 that every conceivable form intermediate to these, exists there, and 

 that these extreme forms, as well as others hereafter to be described, 

 are not only united, but virtually inseparable. Figures 1, 1», I'', and 

 2, Plate 2, are taken from two specimens of Mr. W. C. Lucy's collec- 

 tion, from the Pentacrinites tuberculatus zone, at Fretheme. The side 

 furrow upon these is remarkably distinct, and may be traced to the 

 extreme apex of the beak, giving rise to a corresponding ridge in the 

 smaller valve. This peculiarity, which instantly forces itself upon the 

 attention of the observer, who has previously visited Purton Cliff, 

 as it seldom or never presents itself in specimens from that locality, has 

 doubtless its physiological value. The smaller specimen, Fig. 2, Plate 

 2, exhibits most of the characters of Grypha2a obliqua, but placed in 

 juxta-position with the larger, the possibility of its being other than a 

 less advanced stage of the same species, cannot for a moment be enter- 

 tained. These with Figures 1, 1^, 1^, Plate 5, and Figures 3 and 4, 

 Plate 4, represent full grown individuals, than which very few attain 

 to greater size ; and it is noticeable, that the patriarchal giants of 

 their race, presenting the most distinctive characters of G. incurva, 

 are not found where examples are most readily procurable, and in the 

 largest number, but in higher stages than the A. Bucklandi or P. 

 Tuberculatus zones, particularly in the lower portion of the yellowish 

 grey clays, which lie between the zone of Ammonites obtusus, and 

 that of Ammonites oxynotus. Exceedingly good specimens have been 

 obtained from excavations in Gloucester, which have been placed at 

 our disposal by the kindness of Mr. Henry Arkell ; they are also 

 frequently obtained from farm drain- cuttings in the neighbourhood. 



Figures 3, 3*, 3^ and 4, 4*, 4^ Plate 2, represent specimens of the 

 dwarfed variety, which occurs in the upper portion of the yellowish 

 grey clays above alluded to, where they assume a somewhat marly 

 character, as seen exposed on the estate of T. B. Ll. Baker, Esq. at 

 Hardwicke, in this county, on the surface of a piece of land called 

 Southfield, not far from the canal bank, on the left hand descending 

 from Gloucester, crossing the sixth bridge. Several specimens were 

 found in a small depression in the soil, which -ndll readily be seen upon 

 entering the field. These dwarfs are placed in comparison with the 

 form last figured, not for the sake of contrast, but in natural ascending 

 order, as its successor and legitimate representative, presenting all its 

 essential characters, exhibiting all its marks of perfect development 



