Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/559

 have been very large, whilst those on the marginal tesserae were very small.

Affinities and differences. — This species resembles Stellaster Berthandi, from the ' Calcaire a Entroques ' of Macon ; it differs, however, from that form in being larger, and in having the interradial spaces more arched and the rays themselves much larger. But the marginal tesserae and discal ossicles are very much alike. The mould, however, does not give the character of the granulations. It differs from Goniaster obtusus, Wr., from the Inferior Oolite of Crickley, in having longer and more lanceolate rays, and from Goniaster hamptonensis, Wr., from the great Oolite of Minchinhampton, in the greater width of its tesserae and length of its rays.

Stellaster Berthandi, Wright.

Diagnosis. — Body pentagonal, sides with arches much flattened ; tesserae thick and narrow, 36 to 40 pairs around the margin of one ray ; under surface of the disk covered with small close-set equal- sized ossicles ; ambulacral furrows wide ; dorsal discal ossicles absent.

Description. — Since Mr. Sharp's specimen came into my hands for description, a plaster mould has been kindly communicated to me by Professor Berthand, of Macon, Saone-et-Loire, France. The original was collected from the ' Calcaire a Entroques,' Macon. I mention it here in connexion with Stellaster Sharpii, Wr., as showing that Goniaster was a type of the Asteridae which prevailed during the first stage of the Jurassic period, as the three forms we now know are all specifically distinct, and belong to the Lower division of the Oolitic series.

Discussion.

Mr. W. W. Smyth commented on the great value of careful observations by local geologists, such as those brought before the Society by Mr. Sharp.

Mr. Etheridge pointed out how a few years ago it was supposed that hardly a fossil was to be found in these Northampton Beds, and that they all belonged to the Great Oolite, and not to the Inferior, an error in which the Geological Survey had shared. The district was, however, now being resurveyed under the new light which had been thrown on the character of the rocks by the extensive quarrying which had taken place during the last few years, and which had afforded the opportunities so judiciously utilized by the author of the paper, who had placed the order of succession and the character of the Northampton Beds beyond dispute.

Prof. Morris had found a difficulty in reconciling the phenomena of the eastern and western Oolitic areas, but considered that the key of the arrangement was to be sought in the district between Northampton and Stamford.

Mr. Sharp briefly replied.

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