FAECAL PELLETS FROM MARINE DEPOSITS 21 



Congo, the description being as follows: "Viele ovale gerundete Korper, warschein- 

 lich die Exkremente von Echinodermen. Bei einigen von ihnen lasst sich deutlich 

 Glaukonitsierung beobachten. Sie variieren in der Lange von o-4-o-8 mm., in der 

 Breite von o-2-o-6 mm." They figure also a pteropod ooze in which there are some 

 similar coprolites. On p. 103 they say: " Den wichtigsten und interessantesten Teil 

 dieser Probe bilden die ovalen Korperchen welche von Sir John Murray fiir Exkre- 

 mente von Echinodermen gehalten werden. Sie wechseln in der Farbung von grau zu 

 braun und dunkelgriin. Sie wurden bereits von der Challenger Expedition erwahnt, und 

 sind seitdem besonders durch Buchanan aus dem Golf von Guinea und von der 

 Kongomiindung bekannt geworden. Buchanan konstatierte, dass mancherorts in einer 

 Tiefe von 50 Faden die ganze Anlagerung aus diesen Exkrementen besteht, und ge- 

 brauchte dafiir die Bezeichnung 'Coprolitic Mud'. Diese Exkremente fanden sich 

 bisher nur in tonigen Ablagerungen in der Nahe des Landes, besonders an der Miin- 

 dung grosser Strome". 



Vaughan (1924) has figured and compared similar pellets from the Bahamas, and 

 oolites from the same region. He says (p. 327): "For some time I thought the ellip- 

 soidal aggregates in the fine-grained muds were to be considered oolite grains, for in 

 external features they are very similar, but the grains in the mud do not exhibit the 

 concentric structure of the ooHte grains. . . . However, the cores of the oolite grains are 

 similar to the grains in the muds, and it may yet be shown that the grains in the mud 

 represent a stage in the formation of oolitic limestone. . . . The origin of the ellipsoidal 

 grains is a puzzle. They resemble in size, form and general structure, glauconite and 

 greenalite grains, and it is probable that when their formation is explained, the ex- 

 planation will be of wide appUcation". In his photographs of sections of pellets from 

 the Bahamas there is, as stated, no trace of concentric structure, nor of localization of 

 any particular material, but there appears to be a darker region round the outside of the 

 pellet, presumably corresponding to a region of slightly finer material, possibly to some 

 extent cemented with mucus or some other material. If this is the case they are similar 

 in structure to the pellets described from the Clyde (Moore, 193 1, 193 1 a; GaUiher, 

 1932, fig. 2). 



Takahashi and Yagi (1929) describe the distribution of similar pellets in various 

 localities in Japan. With the exception of Kasumiga-Ura, which is a nearly fresh-water 

 lake, the pellets were found only in marine deposits, and not in fresh water. The pellets 

 formed in some cases as much as 5 per cent of the deposits, and are described as elongated 

 ellipsoidal, with a diameter of 0-5-1 -4 mm. They were rather soft and friable, and varied 

 in colour from Hght grey to dark green, the apparent density varying from i-6 in the 

 grey to 2-2 in the green ones. In section they appeared, with rare exceptions, to be 

 homogeneous. Takahashi and Yagi compare these pellets with very similar structures 

 from Tertiary deposits, and trace the probable course of glauconization in the recent 

 pellets. With regard to the origin of these pellets they suggest that these are probably 

 the faeces of some mud-eating animal. It is interesting to note that some few of their 

 pellets, although ovoid in outline, had heHcoidal cores. Although I have not so far met 



