438 . Scientific Intelligence. 
sections, mounted in Canada balsam, by transmitted and also 
reflected light, also the surface of the “ aiatinag slice as it 
came from you, in all directions, with one-quarter- and on e-inch 
focus compound powers respectively, I iss unhesitatingy desleae 
that it presents no foraminiferous structu Nor does 
test as the legs of a table to those of a quadruped; while, if such 
be the grounds on which geological inferences are established, 
the sooner they are abandoned the better for geology, the worse 
for sensationalism ! 
The contents of this letter are open to no controversy. My 
Pegg of i ig naga structure has been obtained step by 
own se 
ward my illustrations and descriptions have ear taken. If others 
who have pursued a similar course of instruction differ from me in 
what I have above stated, the question can only be Lpuiee bya 
third party, not on verbal ‘arguments alone, but on a comparison 
of the actual specimens, as prolonged disputation, in raters of 
opinion, soon disgusts everybody but the combatants, and can end 
in nothin vg but a fearful waste of time that might be better 
Note on the Geol logy of Costa Rica. (From a letter to the 
Gian, dated Limon, Costa Rica, Feb, 7th, 1874.)—Nearly all of 
the year 1873, I have been in the mountains of southeast Costa 
ica, with a corps of assistants. In that time, besides eng sized 
collections, half a dozen large vocabularies and the first topo 
graphical i 
notes on the geology. I expect shortly to commence the ascent of 
the volcanoes, and, before you receive this, may have the pleasure 
of standing, the first — man, on the top of Pico Blanco, and 
with a Green’s baromete 
ke unexpected result, suspected this half-year gee has just 
received proofs, in a that I made along the cafion of the 
Reventazon River. The bepress rocks of the se slope 
3 am convinced not ont that they are acces: but that they are 
later than the Eocene. ‘This ws so unlike my preconceived idea 
that I was extremely reluctant to admit the fact, while I fo 
species wg molluses, identical with some found by Dr. Maach on 
e isthmus, and by myself in the late Miocene of Sto. ager 
Besides thie specific identity, the facies of all the species is ex 
ingly modern, and I shall not be surprised if comparison should 
From the w n existence of the sa vires in the West 
Indies and Columbia, and from the asserted finding, b pape 
M t, of Jurassic in the States farther north, ted 
that these reeks were secondary, more especially since “they — 
