Ee ser eae 
Geology and Natural History. 389 
the formerly received opinion. Where this originated I cannot 
learn. From the flank of Pico Blanco I made a rude leveling 
across to the summit of the “ U-jum,” i 
had not seen, is 200 to 300 feet lower. 
I find that “U. i 
Summit 
Its geography has been misstated by some writers, who have 
placed it on a spur of the Cordillera. It is distinctly in the center 
line of the main chain, the waters falling rapidly from it toward 
the two oceans. is connection we have robbed Iraza, the 
Old Harbor, sea level, barometer, 39°042, att. therm. 80, det. therm. 81 
of Peak, - Deg A « 635, 4 “69 
ans. In thi ‘ ; d ; 
_ “show mountain” of Costa Rica, of one of its chief glories. Every- 
body who comes to the country rides up to the crater on mule 
back and then writes a book about his achievement, not omitting 
to state that this is the only point in the world where one can see 
th oceans at once. 
From even as low as 600 feet below the summit of Blanco we 
Saw at a glance thirty miles of the Atlantic, and all of forty of the 
Pacific. This is a little better than a glimpse of near Greytown 
on one side, and a suspicion of the Gulf of Nicoyo on the other, 
which the Iraza (or voleano of Cartago) people get. 
Geologically, Pico Blanco must henceforward be erased from 
the list of voleanos. It is the culminating point of a granite in- 
trusion from below Miocene rocks. say intrusion, after due 
Weighing of probabilities as to Azoic core, which I know will sug- 
gest itself to you. I have not space here to enter into details, 
Syenite has yet been found by me in our conglomerates! 
ile I say it is not a voleano, yet there is a a mass of true 
voleanic rock forming the apex. It is, however, only a dike, laid 
Am. Jour. Sot.—Tuirp Series, Vou. VIII, No. 47.—Nov., 1874. 
25 
