Jurassic Mollusca from Arabia. 11 



that place, at the end of a long valley which runs north from 

 Nobat Dakim. All the remaining fossils were found at the 

 tops of the small cultivated valleys which run up between the 

 low spurs on which the villages of Al-Kura and Samma 

 stand; and there were several more neighbouring valleys of 

 the same sort, with fossils in them in similar situations." 



According to the sketch-map accompanying the specimens, 

 the fossils marked " Nobat " were found between layers of 

 basalt on the western side of Jebel Manif (2500 feet), about 

 7 miles N.N.E. from Nobat Dakim. The villages of Al-Kura 

 and Samma, near which the remaining fossils were found 

 beneath Deccan trap, are at a distance of about 15 miles N.E. 

 of Dihala. 



Only one Cephalopod (the Belemnite) is labelled " Nobat." 

 It is, however, to be observed that the small portions of 

 matrix still adhering to this specimen agree perfectly with 

 the matrix of the fossils from near Dihala, whilst its state of 

 preservation differs entirely from that of the other specimens 

 labelled " Nobat/' 



The Cephalopoda comprise two Nautili, five Ammonites, 

 and one Belemnite. A perfectly flat and smooth internal 

 cast, about 40 mm. in diameter, without any indication what- 

 ever of sutures, is possibly the remains of an Ammonite. 

 The Nautili and Ammonites are contained in a light fawn- 

 coloured limestone ; they are all very much crushed, and in 

 no single instance is it possible to make out a suture-line. 

 Portions of matrix on the Belemnite indicate that that also 

 was obtained from similar rocks. 



Description of the Species. 

 A. Nautiloidea. 



Genus Nautilus, Breyn. 



Nautilus cf. hexagonus, J. de C. Sovverby. 

 (Pi. II. fig. 2.) 



182G. Nautilus hexagonus, J. de C. Sowerby, Min. Conch, vol. vi. p. 55, 

 pi. dxxix. fig. 2. (For references, see A. H. Foord, Cat. Foss. Genii! 

 Brit. Mus. pt. 2, 1891, pp. 235-2-36.) 



Using the name in a broad sense, the genus Nautilus is 

 represented by two examples, about 90 and 95 mm. in 

 diameter respectively. Both are doubtless referable to the 

 same species, but are so very much crushed that their original 

 dimensions cannot now be ascertained. The shell appears 

 to have been rather inflated and rapidly expanding, and 



