111 



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

 to unusual circumstances. Thoiigh mucli of the lava sheet has been re- 

 moved by erosión, a fevr tmncated conical bilis sbow its former level and 

 extent. 



Rosario mountain, a trachytepeak5193 feetbigh (by boiling point), 

 Í8 worth a visit, as it gives an extensiva view. At its base tbere are gold 

 mines, -where the metal is extracted from heematite in primitive native 

 milis called arrastras, consisting of shallow, paved, circiilar pits, round 

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

 a curious mass of vegetation, moulded to the shape of a spo^iting water- 

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

 raboloid form, so tbat 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 fems 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 diver- 

 ted by lavar-flows from volcanoes near Choix, and it retums 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 byrows of single-stemmed cacti, growingin contactto a gi-eat height; 

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

 tree called Bebalama grows in the plain, ithas slender stem, branches, and 

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

 no leaves in Mavch; the sheltered ravines contain some rubber-beañng 

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

 mense sahaura (Cerem gignnteus) 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 coimtry 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 Califomian Gulf — hues of víolet, purple, and rose predomínate— and no 

 Buch displays were seen by the author, since the wonderf ul sunsets caused 

 by the eruption ef Krakatoa. 



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



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



lo«t). Just abo ve this place a very cold night was experienced, with den- 



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



