1 pointed out, there's gravel on the east rim, which is stationary and 



2 then very fine sand is accumulating around the canyon heads. 



3 The question is: Where does it come from, could it come from the 



4 canyon? Well, we don't know that now. 



5 The walls in these high-energy canyons would have many silt and 



6 clay outcrops, they'd be rather steep, extensive bioerosion, and it 



7 would be a mixed shelf sand and silt and clay, and rippled on these 



8 walls in transit to the floor and transported, presumably by axial 



9 currents in the canyons. 



10 On the floor, we would have sand, which is rippled and formed into 



11 large dunes or sand waves. They are transported up and down canyon by 



12 these strong, semidiurnal axial currents, the fines would be separated, 



13 carried out of the canyon and perhaps up into the head region and the 



14 sand would be deposited. 



15 Now, in moderate-energy canyons, it would be very similar to the 



16 high-energy canyons, excepting possibly in the degree of bioerosion on 



17 their walls. If their walls are less steep and more covered with sand 



18 from the shelf, they would possibly have less bioerosion, so there would 



19 be less bioerosion. 



20 Since the axial currents are weaker, you, on the canyon floor, 



21 would have a buildup of silty sand, which is rippled, few large 



22 bedforms, also transported up and down the canyon by more moderate 



23 currents, but they would not be strong enough to extract the fines and 



24 so you'd have sand, silt and clay deposited on these floors. 



25 In the lower-energy canyons, shelf sand would also enter these 



26 across their rims, but there is a question about whether or not there 



27 would be gravel on their east rim, since they don't extend very far into 



28 the shelf. 



29 The question would be: How far does it have to extend into the 



30 shelf to be affected by this westward current and cause a gravel lag to 



31 develop? There would be few silt and clay outcrops because of the low 



32 slope of the walls and the buildup of sand from the shelf moving down 



33 into the canyon. 



42 



