Day—Ancient Beach and Submerged Forest. 109 



eacli row, delineated in fig. 3. This distance the two ranks main- 

 tain to near their rear end, whei'e they again slightly approximate. 

 I have seldom seen a more effective and formidable array of laniary 

 teeth in the jaws of a Sauroid Fish. 



Of such a fish the bone, of which two views are given in Plate 

 IV., from the same formation and locality, is part of the superior 

 maxillary. From similarity of size ; but more especially from the 

 similarity of number, size, and arrangement of the laniary teeth ; 

 from the corresponding degree of antero-posterior compression of 

 the base of the tooth, as shown in Plate IV., fig. 2 ; from the pro- 

 portions of the enameled and cement-covered parts of the crown, 

 and from the shape and degree of curvature thereof, so far as is 

 shown in the least-mutilated teeth (Plate IV., fig. 1), I am disposed 

 to refer this specimen to the same genus and species as the mandible 

 (Plate v.). In one of the large maxillary teeth I found, on scrap- 

 ing away the cement, a slight depression on the outer side of the 

 base, as in the antepenultimate tooth in fig. 1 ; but this is neither 

 so deep or so constant as in Thlattodus. In both the upper and lower 

 teeth of Ditaxiodus a large pulp-cavity remains, partly filled by a 

 lighter-coloured matrix than the outside petrified clay, as shown at 

 Plate IV., figs. 1 and 2. 



Most probably the inner rank of small mandibular teeth were 

 opposed by a similar rank of teeth on the palato-pterygoid jaws 

 parallel with the maxillary rank of laniaries. 



The figures in Plates IV. and V. are of the natural size, and are 

 explained in the text. My best acknowledgements are due to Mr. 

 Cunnington for this and former opportunities of adding to the facts 

 of Palaeontology. 



EXPLANATION OF PLATES IV. AND V. 



Plate IV' — Portion of superior maxillary bone and teeth of Ditaxiodus impar. 

 Fig. 1. Outer side. 



2. Alveolar surface. 



Plate V. — Portion of dentary element and teeth of lower jaw of Ditaxiodus impar. 

 Fig. 1. Outer side and rank of teeth. 



2. Inner side and ranis of teeth. 



3. Anterior or syraphysial end. 



4. Under yiew of part of the dentary. 



IV. — On an Ancient Beach and a Submerged Forest, neak 



VVlSSANT. 



By E. C. H. Day, F.G.S. 



(PLATE VII.) 



ME. PEESTWICH has, in two valuable papers, published by 

 the Geological Society,^ given a very detailed description of a 

 raised beach and associated recent accumulations, upon the coast in 

 the vicinity of Sangatte, a village about five miles from Calais. In 

 the second of these papers, the author mentions that he proceeded 



1 Quart. Journ. Geol. Soc, vol. vii., p. 274, 1851 ; and vol. xxi., p. 440, 1865. 



