Correspondence — W. J. Barhas. 287 



sectional area as is it approaches Portland. It is evident that the 

 force of the insetting tidal current, assisted by the prevailing wind, 

 must increase in angular intensity as it approaches and is deflected 

 from the hollow of the bend of the bank produced by the pro- 

 montory of Portland. At this point also will the wind waves have 

 the greatest power. It is also easy to understand that the amount of 

 material cast up above high water will vary as the energy of wave 

 action varies, and consequently the largest stones will be thrown up 

 at the point of intensest action. As the shingle of all sizes travels 

 eastward along the beach the smaller stones are cast up first, the 

 larger ones being weightier have less lateral upshore movement, and 

 so travel further. In fact I conceive the phenomenon must neces- 

 sarily follow from the application of the known mechanical law of 

 the inclined plane — the greater weights travelling up a more ex* 

 tended and therefore lesser gradient, until they come within the 

 range of waves sufficiently powerful to cast them upon the bank 

 itself. 



It is quite clear to me that the whole bank is the result of causes 

 now at work, and which have continued with remarkable uniformity 

 since the last relative change of level of land and sea. With Mr. 

 Fisher I agree that the irregular shingle-banks and inclosed lagoons 

 on the coast of Ireland, mentioned by Mr. Kinahan, are not at all 

 parallel phenomena. 



Heath House, Blundellsands, T. Mellard Keade, C.E. 



Liverpool, April Ith, 1874. 



BYBOBUS, A COAL-MEASURE FISH. 



Sir, — While examining a work by Pictet this morning, entitled 

 "Traite de Paleontologie," I stumbled upon the following remarks 

 in the second volume, p. 256; he is speaking of Hyhodus : "Beau- 

 coup d'autres sont connues seulement par leurs dents. Deux especes 

 sont citees dans les terrains carboniferes, Ce sont les Hyhodus car- 

 honarius et vicinalis, Griebel de Wettiu." 



His authority for this statement is Giebel, in his work on the 

 " Fauna der Vorwelt." I was much surprised, and yet gratified, to 

 find that my opinion of Hyhodus being a Coal-measure Fish, arrived 

 at quite independently, should be corroborated by so eminent a 

 palaeontologist. Of course my statement that Hyhodus had never been 

 described previously to my paper as a Coal-measure Fish is erroneous; 

 but considering that Agassiz, Owen, Huxley, Pander, Munster, 

 M'Coy, Newberry, etc., etc., do not refer to the work, nor to the fact 

 in any way, I consider myself quite justified in making it. However, 

 Giebel and I have arrived, quite independently, at the conclusion that 

 the teeth of Hyhodus are to be obtained in the Coal-measures, and 

 we coincided so far that, in a list of Palaeozoic Fishes I am preparing, 

 I had actually named our English Coal-measure Hyhodus, H. carhon- 

 arius. This name, however, I must withdraw, if my species does 

 not resemble his ; but, unfortunately, I have not any means of com- 

 paring their characteristics : for Giebel's work is not among the 



