FAECAL PELLETS FROM MARINE 



DEPOSITS 



By Hilary B. Moore, b.Sc. 

 (Text-fig. i) 



IN many accounts of marine deposits, mention is made of small ovoid bodies, of more 

 or less the same consistency as the matrix in which they are found, and forming up to 

 30 per cent and in rarer cases as much as 100 per cent of the deposit. 



Since these bodies are found in both recent and fossil marine deposits, and are of 

 world-wide occurrence, and since various theories have been suggested as to their 

 origin, it is thought desirable to bring together here the facts which are known as to their 

 nature and occurrence. 



Buchanan (1890), in an account of some mud taken off Arran in the Firth of Clyde in 

 1878, describes elongated pellets which could be separated from the ground-mass of the 

 mud by elutriation. He rightly ascribes to these pellets an animal origin, but intro- 

 duces an error which has been followed by several subsequent authors in saying that 

 they are the faeces of ophiuroids. The error arose from the fact that he took the mud by 

 means of an iron bucket which skimmed the surface of the mud. This collected at the 

 same time both the surface mud with its contained pellets, and a large number of 

 ophiuroids, probably A7nphmra chiajii. He therefore drew the conclusion that these 

 were responsible for the production of the pellets, which, he says, were formed by the 

 trituration of sand grains in their stomachs. In the same paragraph, however, he states 

 that in those particular muds there is practically no sandy material. In any case, ex- 

 amination of Amphmra chiajii shows that it does not form pellets of either this, or any 

 other regular shape, and that its excreta are in very much larger masses than the mud 

 pellets. Further, it has since been demonstrated (Moore, 193 1) that the pellets in these 

 particular muds are formed by Maldanid worms. And the worms themselves are 

 rarely taken in any quantity by an instrument which merely skims the surface of the 

 mud. 



Buchanan (1890) further records a similar mud taken in 1879 in the Sound of Rasay 

 in 155 fathoms, and again he says: " Sticking to the outside of the bag were many large 

 ophiuroids, which will account for the coprolites (Extract from the Deck Book of the 

 Steam Yacht ' Mallard ', 1879)." He continues: " Later, in the year 1886, when in charge 

 of the expedition to survey the Gulf of Guinea, in the steamship ' Buccaneer', I found 

 the same thing almost universal all along the African coast, and developed in the most 

 remarkable manner on the coast flat within a considerable radius of the mouth of the 

 river Congo. Here it was necessary to introduce new designation for muds, and in this 

 district, the most frequent entries in the deck book as to the nature of the bottom are 



