MAEINE BIOLOGICAL STATION AT POET BEIN. 57 



Trochus, of various calcareous polyzoa, such as Cellaria 

 flsttdosa, Cellepora pu?nicosa, and lepralids, of Balanus 

 and Serpula, and of various echinoderm plates and spines 

 and the whole shells of Echinocyamus pusillus. The 

 deposit, when it comes up in the dredge, is of a gleaming 

 whiteness, and has a very characteristic appearance. Such 

 a deposit as this would form a rock almost wholly made 

 up of fossils, and might compare well with some Tertiary 

 fossiliferous deposits, such as the Coralline Crag. 



A little further north, along the east coast of the Isle of 

 Man, at about a corresponding depth and distance from 

 land, we meet with a purely vegetal deposit formed of the 

 nullipores Lithothamnion and Melobesia. On the other 

 side of the island, again, between Port Erin and the Calf, 

 at a depth of 18 fathoms, there is a tract of sea-bottom 

 which, when brought up on deck, looks, at the first glance, 

 like a peculiarly fibrous sand, but a closer examination 

 shows that it is entirely composed of the comminuted 

 plates, and especially the spines of echinids, chiefly 

 Spatangus. I do not remember to have met with a 

 reference to material such as this either amongst recent 

 or fossil deposits. 



The remarkable deposit of cemented shells, which was 

 described in last year's report, from a locality half-way 

 between the Calf and Holyhead, is also found off King 

 William's Bank, between Eamsay and St. Bees. Plate 

 II. represents a piece of this material. 



The variety that is noticed in sub-marine deposits round 

 the Isle of Man, from depths of 15 to 35 fathoms, as 

 brought up in the dredge, is very striking. It is remark- 

 able how differing proportions in the mixtures of sand, 

 gravel, and shells give rise to very different colours and 

 general appearance in the mass. As seen, when tumbled 

 out of the dredge on to the deck, some deposits are white, 



