Correspondence — Mr, T. Mellard Reade. 573 



The author exhibited and described an astragalus of Igiianodon from the col- 

 lection of E. P. Wilkins, Esq., F.G.S. The bone was beUeved to be previously 

 unknown. It is a bone of irregular form, having on its lower surface the charac- 

 tei-istic pulley-shape of a movable hinge-joint. The upper surface presents a form 

 exactly adapted to that of the distal end of the tibia, so that the applied surfaces 

 of the astragalus and tibia must have interlocked in such a manner as to have pre- 

 cluded all motion between them. The author remarked upon the interest attaching 

 to this fact in connexion with the question of the relationship between the Dinosauria 

 and Birds. 



4. " Note on a very large Saurian Limb-bone, adapted for progression upon 

 land, from the Kimmeridge Clay of Weymouth, Dorset." By J. W. Hulke, Esq., 

 F.R.S., F.G.S. 



The bone described by the author presents a closer resemblance to the Croco- 

 dilian type of humerus than to any other bone, and he regarded it as the left 

 humerus of the animal to which it belonged. Its present length is 54 inches, but 

 ■when perfect it could hardly have been less than 63 inches in length. The middle 

 of the shaft is cylindroid. Its transverse section is of a subtrigonal figure, and 

 presents a large coarsely cancellated core, inclosed in a compact cortical ring. 

 The bone is considerably expanded towards the two extremities ; the distal articu- 

 lar surface is oblong, and divided into a pair of condyles by a very shallow vertical 

 groove ; below, the anterior border, in its proximal half, is much wider than the 

 corresponding portion of the posterior border, and is flattened and produced down- 

 wards into a ventrally projecting crest ; and the distal half of this border forms a 

 thin, rough crest, projecting forwards. The presence of these crests distinguishes 

 the present humerus from those of Pelorosauriis and of Ceteosaitrits Oxoniensis ; 

 but the general correspondence of the bone with the humerus of the latter species 

 leads the author to refer it provisionally to a species of Ceteosaurus, which he pro- 

 poses to name C. kiimero-cristaiiis. 



Discussion. — Mr. Seeley remarked that the internal structure of the bone re- 

 sembled that found in Gigantosatirus, and the general form of the humerus was 

 such as might be expected did it belong to an animal of that genus. 



5. A despatch from Mr. Alfred Biliotti, British Vice-Consul at Rhodes (dated 

 June 16, 1873), communicated by H. M. Secretary of State for Foreign Affairs, 

 and relating to the volcanic outburst in the island of Nissiros, one of the Sporades, 

 in which there existed a volcano supposed to be extinct. Shortly before the lOth 

 June new craters opened in this volcano, and from them ashes, stones, and lava 

 "were ejected ; many fissures, from which hot water flowed, were produced in the 

 mountain, and the island was daily shaken by violent earthquakes. From Rhodes, 

 at a distance of about 50 miles, the smoke rising from the new craters could be seen. 



ooi^E-iEsiPon^nDiEisrczE!. 



THE CHESIL BANK. 



Sir, — Having within the last three weeks examined the Chesil 

 Bank, I was much pleased to see by your November Number that 

 the Eev. 0. Fisher offers what I consider the true theory of that 

 remarkable phenomenon, and one identical with the explanation 

 noted down by me at the time. 



The bank is undoubtedly the resultant of the mechanical action 

 of the tides and prevailing winds, as modified by the leading features 

 of coast configuration. Its regularity — appearing almost as an 

 artificial embankment — is most striking, and points to a wonderful 

 uniformity of action over a lengthened period of the i^roducing 

 causes. At Burton Clifi", its western extremity, it commences as a 

 beach, gradually develojjing as it passes over the low lying land to the 

 eastward into a bank or ridge with seaward and landward slopes, 

 until it approaches the Coast Guard Station, where it again becomes 

 a beach against a low cliff, cut by the sea into loose materials 



