chap. ix. not Horizontal. 255 



E is well developed on the south side, but absent on the north side of the valley ; 

 though not continuously united with (E) of the former section, it apparently 

 corresponds with it. 



F This is the surface-plain, and is continuously united with that which stretches 

 like a fringe along the coast. In ascending the valley it gradually becomes 

 narrower, and is at last, at the distance of about ten miles from the sea, reduced 

 to a row of fiat-topped patches on the sides of the mountains. None of the lower 

 terraces extend so far up the valley. 



These five terraces are formed of shingle and sand ; 

 three of them, as marked by Capt. Basil Hall (namely, 

 B, C, and F), are mnch more conspicuous than the others. 

 From the marine remains copiously strewed at the 

 mouth of the valley on the lower terraces, and south- 

 ward of the town on the upper one, they are, as before 

 remarked, undoubtedly of marine origin ; but within 

 the valley, and this fact well deserves notice, at a dis- 

 tance of from only a mile and a half to three or four 

 miles from the sea, I could not find even a fragment of 

 a shell. 



On the inclination of the terraces of Coquimbo, 

 and on the upper and basal edges of their escarpments 

 not being horizontal. — The surfaces of these terraces 

 slope in a slight degree, as shown by the last two sections 

 taken conjointly, both towards the centre of the valley, 

 and seawards towards its mouth. This double or 

 diagonal inclination, which is not the same in the 

 several terraces, is, as we shall immediately see, of 

 simple explanation. There are, however, some other 

 points which at first appear by no means obvious, — 

 namely, first, that each terrace, taken in its whole 

 breadth from the summit-edge of one escarpment to 

 the base of that above it, and followed up the valley, is 

 not horizontal ; nor have the several terraces, when 

 followed up the valley, all the same inclination ; thus 

 I found the terraces C, E, and F, measured at a point 

 about two miles from the mouth of the valley, stood 

 severally between fifty-six to seventy-seven feet higher 

 than at the mouth. Again, if we look to any one line 



