332 KEPORT— 1894. 



4. As examples of a few peculiar and specially noteworthy deposits 

 which are not simply * terrigenous ' in their origin, the following may be 

 mentioned : — 



South-east of the Calf Sound, about two miles out, at a depth of 20 

 fathoms, there is a white shelly sand which seems to be almost wholly 

 composed of animal remains. There are broken fragments of the lamelli- 

 branchs Pecten, Auomia, Pectunctdus, Mactra, Venus, and Mytilus, of the 

 gastropods Cyprcea, Buccinum, Emarginula, Purpura, and Trochus, of 

 various calcareous polyzoa such as Cellariajistulosa, Cellepora pumicosa, 

 and lepralids, of Balanus and Serpula, and of various echinoderm plates 

 and spines, and the whole shells of Echinocymnus 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 Lithothaninion 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. 



The variety that is noticed in submarine deposits round the Isle of Man, 

 from depths of 15 to 35 fathoms, as brought up in the dredge is very 

 striking. It is remarkable how differing proportions in the mixtures of 

 sand, gravel, and shells give I'ise to very difierent colours and general 

 appearance in the mass. As seen when tumbled out of the dredge on to 

 the deck, some deposits are white, some yellow, some grey, some reddish, 

 of various tints from pink to ruddy brown, and others darker, of all 

 shades of brown and dark grey. It is curious how, even in a compo- 

 site deposit made up of many different constituents, there is usually a pre- 

 vailing tint ; for example, the bottom at Station 6 on May 27, although 

 composed (see p. 321) of mud, sand, nullipores, shells, and stones, was dis- 

 tinctly of a rich ruddy brown tint. The importance of this presence of 

 prevailing colours in the various submarine deposits is obvious in its 

 bearing upon the colours and habits of animals. 



Another very remarkable sea-bottom is one which takes the form of 

 irregular calcareous masses, cementing together the dead shells and sand 

 grains which are lying on the bottom, and making lumps like 'clinkers.' 

 Hence the spot whei-e it is found is called by the trawlers the ' Black - 

 smitli's Shop.' It is about 25 miles S.S.W. of the Calf of Man (see 

 PL I.), in ordinary clear weather the Chicken Rock Lighthouse just 

 dipping and the stack at Holyhead just rising above the water, and the 

 depth is about 25 fathoms. We have also heard of a similar bottom of 

 cemented shells between Ramsey and North Lancashire. Mr. Leicester 

 has found the following shells in the concretions : — Pecten opercularis, 

 Cyprina islandica, Venus lincta, Cardium echinatum, Niicida niicleus, 

 Scrobiodaria alba, Lucina borealis, and Turritella terebra. There is 

 a line lump of this deposit in the Biological Station at Port Erin, and 

 Ave have presented another piece to the Jermyn Street Museum in 

 London. Mr. W. W. Watts, of the Geological Survey, has made a 

 careful examination by thin sections of the latter specimen, and he has 



