Ill 



by algas of a very deep green colour — a remarkable example of adaptation 

 to unusual circumstances. Though much of the lava sheet has been re- 

 moved by erosion, a few truncated conical hills show its former level and 

 extent. 



Eosario mountain, a trachyte peak 5 193 feet high (by boiling point), 

 is worth a visit, as it gives an extensive view. At its base there are gold 

 mines, where the metal is extracted from haematite in primitive native 

 mills called arrastras, consisting of shallow, paved, circular pits, round 

 which heavy stones are dragged by mule power. On Rosario mountain was 

 a curious mass of vegetation, moulded to the shape of a spouting water- 

 fall; it extended from one rock-ledge to another forty feet higher, in a pa- 

 raboloid form, so that the water would run over its surface in an even sheet. 

 The mass was as dry as hay, but seemed to be a selaginella. There are se- 

 veral sorts of ferns here, which roll up tight in the dry season, and respond 

 to a small shower of rain by immediately expanding the evergreen upper 

 sides of their fronds. Deer and jaguars are common about Rosario. 



Below Baca the river takes a sweep to the west, having been divert 

 ted by lava-flows from volcanoes near Choix, and it returns to its general 

 direction near Toro; most of the intervening country has been swept clear 

 of lava, exposing syenite. At Toro several hills, like bench-marks in an 

 excavation, show the former level of the lava. The ranches here, are fen- 

 ced by rows of single-stemmed cacti, growing in contact to a great height; 

 they are only six inches thick, # but absolutely unclimbable. A singular 

 tree called Behalama grows in the plain, it has slender stem, branches, and 

 twigs of a bright-green colour, and shower of beautiful yellow flowers, but 

 no leaves in March; the sheltered ravines contain some rubber-bearing 

 plants, though they are not plentiful, owing to the long drought. The im- 

 mense sahaura ( Cereus giganteus) or pillar cactus of the Gila valley does 

 not grow so far south. Between Sinaloita and Ocolome, on the river, there 

 are outcrops of mica schist and slate, the general strike of the cleavage 

 being a little west of north; below this the country becomes more level. 

 At the town of Fuerte the river is 300 yards wide, with a rapid current 

 over coarse sand, but only three or four feet deep. There is a colouring 

 about the gorgeous sunsets of the plain which is peculiar to the shores of 

 the Calif ornian Grulf — hues of violet, purple, and rose predominate— and no 

 such displays were seen by the author, since the wonderful sunsets caused 

 by the eruption ef Krakatoa. 



At San Bias there is a bar of rock across the stream; it is apparently 

 metamorphic, and contains dark-red and green jaspery bands (specimen 

 lost). Just above this place a very cold night was experienced, with den- 

 se fog — a suprising thing in the hot country, and the only fog seen by the 



