480 MR. A. STRAHAN ON SUBMERGED LAND-SURFACES [Aug. 1 896,, 



6. This blue silty clay precisely resembles no. 4. It ranges from 



5 to 7 feet in thickness. 



7. The second peat is an impersistent brown band never exceeding 



8 inches, and averaging about 3 inches in thickness. Its upper 

 and lower limits are indefinite, and it suggests merely that 

 for the time being plant-remains were accumulating more 

 rapidly than mud. Mr. Eeid describes it as 'a marsh-peat,- 

 apparently composed mainly of sedges (Scirpus maritimus)? 



8. This resembles nos. 6 and 4, and is from 5 to 7 feet thick. In 



its upper part, immediately under the peat-bed no. 7, it con- 

 tains shells, among which Mr. Eeid identifies Melamjpus 

 myosotis, Helix arbustorum, Pwpa, and Hydrobia ventosa. 



Upright stems of a sedge, probably Scirpus maritimus, occur 

 throughout this bed as through all the other silts. 



9. This peat occurs at or close to the bottom of the dock — that is, at 



20 feet below Ordnance-datum. It rarely exceeds 8 inches in 

 thickness, but is persistent. In several places it is made up 

 almost entirely of large timber, both trunks and stools of trees,- 

 while in one section roots and rootlets extending downward 

 from the peat into a soil composed of disintegrated Keuper 

 Marl were finely displayed. I give the section at this point 

 in full:— 



Section about the middle of the North-western side of the Dock. 



feet, inches., 



2. Brown clay with Scrobicularia to 1 



3. Sand and gravel with recent marine shells 5 



Line of erosion. 



5. Peat 1 6 



6. Blue silty clay 7 



7. Peat 3 to 4 



8. Blue silty clay 5 



9. Peat with large logs, including some of oak 3 to 8 



Decomposed green Keuper Marls, traversed by roots in 



position of growth and joining on to the peat above. 

 Among the roots are some of conifers 3 



Close by this spot the rock-surface rises on the flanks of one 

 of the shoals referred to above ; the beds thin out in succession 

 against this slope (as shown in the section on p. 478), and it 

 is for this reason that the sequence ends here with No. 9. 

 The clear exposure left no doubt that the roots and rootlets 

 were embedded in the position of growth in their native 

 soil, nor was there any difficulty in tracing them upward 

 into the mass of rotten wood that constituted the peat. In 

 examining this section I had the advantage of the assistance 

 of Mr. Storrie, to whom I am indebted for the identification 

 of the woods. 



Mr. Eeid describes a specimen of this peat collected at a 

 few yards distance as consisting of ' a tough mass of vegetable 

 matter, principally sallow and reed, both roots and stems. 



