F-9 



to have directly followed the phase of activity that pro- 

 duced the dendritic drainage network. In Baltimore Canyon, 

 the axial downcutting phase has been superceded by a phase 

 of axial filling, leading to the formation of the broad 

 thalweg floor. 



Kelling and Stanley (1970) noted four reflector zones 

 in their study of the Baltimore Canyon. Their uppermost 

 group of reflectors is thick (105-150 m) , and is discordant 

 with the group beneath. The second reflector interface 

 appears to have an angular contact, while the lowermost 

 interface is concordant but represents a lithological break 

 rather than a stratigraphic discontinuity. When Kelling 

 and Stanley's cross-sectional profiles are compared to our 

 survey to locate surface exposures of these reflectors, the 

 topmost discordant contact intersects the thalweg axis at 

 about 190 m, the angular contact is at about 230 ra, and the 

 lowermost contact is at about 4 70 m. Outcrops noted in the 

 camera sled survey are consistently located in the lower 

 reflector zones. 



Paleontologic determinations by Stetson (1949) , Gibson 

 et al. (1968) , and in this report (Tables Fl and F4) are 

 all Pleistocene to Recent in age. These materials are almost 

 entirely clays, silts and sands, and were collected from the 

 veneer layers or the thalweg floor cover. Correlation of 

 reflectors to other adjacent areas by Kelling and Stanley 

 (1970) led them to conclude that their middle reflector 

 zones were middle to upper Tertiary, and the lowermost zone 



