128 



DESCRIPTION OF PLATES. 



Fig. 1st — Lithograph of a cast of an impression of a 

 medusa, or sea nettle, as the animal is commonly termed ; 

 which retains, in a very perfect manner, the proofs of a similar 

 conformation and constitution to those inhabiting our present 

 seas. The class of physical conditions as respects land and 

 water, and meteorological also, seems to have been the same as 

 those which now obtain, so as to leave the solid memorial of 

 its evanescent existence in the ancient strand. 



In my daily walks along the sandy beach between Egremont 

 Ferry and Sea Bank, in the summer months, after the reflux 

 of the tide, and especially after a few hours of clear sunshine, 

 my observation has been drawn to hundreds of the impres- 

 sions of medusa that have been left in the sand, varying in 

 size from 3 to 18 inches in diameter, and of several species. 

 These impressions almost always assume the forms of the 

 perfect animals; and their surfaces, when desiccation has 

 been complete, are covered with a very tliin film of gbsten- 

 ing animal matter — the only apparent remains of the animals ; 

 and, according to the volumes of their masses, the impres- 

 sions left are less or more deep in the sand. The larger masses, 

 of course, being always deeper than the smaller. From the 

 outer margin of these impressions, all round, there is a slope 

 downwards and inwards, at an angle generally of about 45°, 

 upon which is retained very distinctly the fringed and concen- 

 tric lines of the lower sides of the discs, also the steps, as it 

 were, of the progressive stages of contraction dining the pro- 

 cess of desiccation. 



The cast of the ancient medusa has precisely the same 

 conformation in every respect on its margin, and stands in 



