" Physiography of the Isthmus of Chocé. 877 
of this remarkable tree, I have seen nowhere in all my travels 
mangle columns of such size. 
_ One species of fern within this section descends to the tide- 
water mark in the same way as another species of apparently 
ine same genus on the Atlantic. These two sea-side ferns thus 
may be looked at as the alpha and omega of filical growth, hold- 
lng respectively both termini of the isthmus line. 
é fauna rapidly decreases, clearing the scene for only a few 
orders and families of lower organization. 
The travelling line through the mangrove belt amounted to 
ut two miles, 
Section X. The Beach (La playa of the natives)—This narrow 
‘gee! neck of land is separated from the main by a narrow 
y. It is a mere gain from the salt water, made by the free 
beat of the ocean wave, the maximum rise of which amounts 
to about fifteen feet. 
The formation of an eastern equivalent within the Gulf of 
Urabi seems to be prevented there by the peculiar stowage of 
emersion, where the tidal movements do not change over two 
sg open beach on the Pacific forms the Peninsula of Para- 
cuchichi, named after one of the three rivers emptying their 
vaters into the ocean in its immediate neighborhood. In fact 
> seaward tendency of their currents has been the principal 
‘geney in the formation and partial detachment of this conti- 
tental appendix, as we may call this peninsula. 
aut top of this beach above high-tide mark is erowned by a 
’se growth of brushwork, sparingly interspe: with single 
dad sha size, and outwardly lined by a dense row of mag- 
at Cocos palms, bhp 
The fauna upon this outlying flat is entirely littoral and but 
d. Ye. 
® flora is a motley growth of seashore plan 
tal forms, The orders of Apocynacex, Bignoniacee, Cassicex, 
Mosega : al 
Am i] Con . | 
Ricuos the latter bunches of a graceful Uniola were very con- 
ous, 
a distance across the bay (bahia ensenada) and the beach is 
ut three quarters at ae : 
: as preceded it should be rem 
ssurements are aly approximative, having been taken from 
Tough field notes. ; 
D. 0,, February, 1859. 
ND SERIES, Vor. XXVI, No. 81.—MAY, 1869. 
49 / 
