4-42 ON THE FAUNA AND BOTTOM-DEPOSITS NEAR THE 30-FM. LINE 



contained living protoplasm when captured, were picked out from 

 weighed quantities of the samples and mounted by Mr. Worth, the 

 species being afterwards identified by Mr. Worth and myself working 

 together. 



[Although numerically well represented, the Foraminifera do not 

 appreciably affect the percentage of carbonate of lime in the sample. 

 Thus, although 103 VII. with 203 foraminifera in 0-13 grams has 

 the high percentage of 40"15, this is due to the abnormal amount 

 of shell in the coarser grades of the sample; for 83 VII. has an 

 even higher percentage of 47*83 of carbonate of lime with only 93 

 foraminifera to 0-13 grams, and other similar examples might be 

 instanced. 



This is not surprising when it is remembered that it would take to 

 cover 13 sq. cms. about 5500 grains of sand of the largest size that 

 could pass a half-millimetre mesh, while the actual number of grains 

 present in such an area from most of the line sands would probably be 

 from 16,000 to 20,000. The numerical proportion of 200 foraminifera 

 would thus be small, and their chambered structure, as compared with 

 the solidity of the sand grains, would render their proportionate weight 

 even smaller. 



Foraminifera are found in the medium sands (Grade VI.), the fine 

 sands (Grade VII.), and the silts (Grade VI 11.). They are more 

 numerous in VII. than in VI., and more numerous in VI. than in VIII. 

 Only the Foraminifera from Grades VI. and VII. have been thoroughly 

 examined. These have been recorded in Section V., under the headings 

 of the different orounds. 



The silts contain numerous foraminifera of small species and small 

 specimens of foraminifera of large species. As a result of floating 

 them from the silts it was found that many species sparingly repre- 

 sented in either grades VI. or VII. were all present in almost every 

 sample of silt, as well as species entirely absent from grades VI. 

 and VII. 



Among the species sparingly represented in VI. and VII., but 

 frequent in the silts, are Glohigerina hidloidcs (very frequent), Bvlimina 

 pupoides, Lagena striata, Bolivina dilatata, Folymorphina ladca, and 

 Spirillina vivipara. 



The species present in the silts but not found in VI. and VII. are 

 Cristdktria crepidida, Nodosaria scalaris, Nodosaria laevigata, Nodosaria 

 comrmmis, Bolivina punctata, Ha2)lop]iagmium canariensis, and Lagena 

 lagenoides. 



In some few cases a census was taken of the number of Foraminifera 

 to be found in 13 centigrammes by weight of fine sand, spread out to 

 cover 13 sq. cm. in such manner as to present a single layer of sand 



