FROM THE EDDYSTONE GROUNDS TO START POINT. 385 



"Dredging 85 is remarkable for the manner in which the quartz grains 

 have been rounded and polished, and also for the extremely coarse texture 

 of the 'fine sand,' VII. As has been pointed out, this grade may either have 

 a maximum coarseness, in whicli all the grains are of such size as to barely 

 pass through the 0*5 mm. mesh, or may approximate to silt. In the present 

 instance the maximum coarseness is closely approximated. (The actual silt 

 only forms 0-6 per cent, of the whole sample.) The greater portion of the 

 sample is almost uniformly distrilnited between III., IV., V., and VI., a 

 feature which does not recur. The average grade is 4'597, or almost a mean 

 between IV. and V. The conditions at this point, therefore, are unfavourable 

 to the existence of either coarse gravel or fine sand ; of the first, it is 

 suggested, because the strong wave actions breaks up all large particles, of 

 the second, because the same action will not allow small particles to settle. 

 Add to this the rounded and polished quartz grains, grains rounded as they 

 are practically never found on any beach, and almost every individual grain so 

 polished, and the conclusion should apparently be that here is a centre of 

 wave action. And yet it lies below the 30-fathom line. But at the same 

 time it lies under and to the westward of the Eddystone reef, which, rising 

 above low- water, meets and breaks the south-west Channel seas. 



" The sudden check to the great Channel rollers can certainly not be effected 

 without the accompanying creation of intense currents in the neighbouring 

 depths, and these it is that must be looked to as providing the necessary 

 abrading forces. That these forces only operate at intervals may be gathered 

 from the occurrence in this storm-washed sand of fair-sized specimens of 

 Rotalia beccarii and Miliolina seminulum. The more delicate foraminifera 

 are, however, conspicuously absent. 



" The sand grains at 87 also show a similar but not equally finished polish. 

 This point, however, lies further to the north of the highest point of the 

 reef. To the north-west of the Eddystone the Hand Deeps also take a share 

 in arresting and converting the surface-wave motion. 



" Between the reef and the Hand Deeps the back-wash, refiux currents or 

 arrested and converted wave motion have scooped and maintain a channel, 

 represented by the incurve of the 30-fathom line on the chart. All around 

 the margin of this area there is evidence of wash, which must result in the 

 formation of a considerable amount of fine detrital matter, and this not being 

 able to settle when formed is constrained to collect in the (piieter but still 

 disturbed waters of the centre of the channel and forms the deposit at 89B, 

 56-S per cent, of which is fine sand, a line texture, but not comparable with, 

 say, 92, which lies well clear of the reef and has 90 9 per cent, of fine sand, 

 or with 102, 91, and 104, with 85-4 per cent., 82-7 per cent., and 95-8 per 

 cent, of fine sand respectively. It is, however, more nearly comparaljle with 

 90, which lies at the northern extreme of the eastern Eddystone channel and 

 has 68 8 per cent, of fine sand. Dredging 89B also difi'ers from all the other 

 fine texture sands in having a large percentage (29-2 per cent.) of medium 

 sand. 



" The conclusion which apparently follows these considerations is that the 



