282 PROF. E. HULL, LL.D., ETC., ON THE SUB-OCEANIC 



In a distance of about 20 miles, it descends from the plain 

 of the Continental Shelf at 200 fathoms to a depth of 1,380 

 fathoms, having made a bend westwards about lialf-way 

 down from the apex to the embouchure. The direction of 

 this indentation points towards the mouth of the river 

 Caneira, though the soundings are insufficient to indicate 

 the connecting channel. 



(b.) The Arosa. — This stream probably formed a junction 

 with the river Lerezo Veda before entering the head of the 

 deep and Avide canon which descends from the Continental 

 Platform at the 200-fathom line and opens out on the deep 

 ocean at about the 1.000-fathom line, after a course of 

 35 miles, in long. 9° 45' W. and lat. 42° 35' N. The form of 

 the contours indicate the occurrence of Avide platforms 

 bounded by cliffs on either side of the canon. 



(c.) The Lima. — The platform along this part of the coast 

 being narrow, the head of this canon (long. 1)° 5' W.) 

 approaches to within 20 miles of the mouth of the Lima at 

 Viauna. At its upper part the canon is narrow, and descends 

 within a distance of 10 miles to a depth of 1,137 fathoms 

 ((5.822 feet) below the surface of the ocean; or 5,622 feet 

 below that of the margin of the platform ; absence of 

 soundings prevent any attempt to connect the canon with 

 the river itself across the platform, but there can be little 

 doubt of the continuity of the channel. 



{d.) The JJouro. — The decisive bend inwards of the 200- 

 fathom contour for a distance of 8 or 10 miles opposite the 

 mouth of this river leaves no doubt that we are here in the 

 jDresence of its submerged channel, and the curves of the 

 100 and 50-fathom contours enable us to trace the channel 

 across the platform to a distance of only 14 miles from the 

 mouth of the river itself below Oporto. Owing, however, 

 to the absence of soundings in the deeper portions of the 

 sub-oceanic bay, the exact form of this part of the channel 

 cannot be determined, but sufficient remain to show that 

 the river formerly entered the outer ocean through a wide 

 bay and rapid descent at a depth of about 1,500 fathoms.* 



* The fewness of the soundings in some parts of the ocean-bed off the 

 coasts of Sjmin and Portugal makes the attempt to restore the old river 

 channels the more difficult. I have been favoured by H.S.H. the Prince 

 of Monico with the tabulated results of a large number of soundings made 

 during the years 1885-1888 and 1891-1896 during cruises in the " Hiron- 

 delle " and " Princess Alice " off these coasts, but I have not yet found 

 time to protract them on to the chai'ts (1899). 



