Barometric Anomalies about the Andes. 385 
traces of vertebrate life, in the form of a few minute fishes, In 
England the earliest fishes are now supposed to occur in the up- 
per Ludlow, the so-called “ fish defences” in the lower rocks, 
having been shown to be erustacean. ‘The fragments of jaws, 
teeth and skin found in the “bone-bed” of the upper Ludlow, 
however, do not seem to be capable of being referred with abso- 
lute certainty to the class of fishes, since the opinions of palee- 
ontologists are divided with regard to the larger part, if not all, 
of them. E 
Our author, therefore, seems to us justified in asserting that, 
looking at the Silurian System as a whole, we know that its 
chief deposits (certainly all the lower and most anterior) were 
formed during a long period, in which, while the sea abounded 
With countless invertebrate animals, no marine vertebrata had 
been called into existence; that these may yet be found is 
certainly not impossible; but every year of active exploration all 
over the world diminishes the probability of such an event, and 
should make us more unwilling to accept as a fact any supposed 
saat of the kind, unless substantiated by undoubted evi- 
ne 
€. 
In taking leave of our author, we feel strongly impressed with 
é change which under his guidance, been wrought in 
our knowledge of the lower fossiliferous strata during the last 
ew years; the impulse which his labors have given to pa 
zoic geology is everywhere felt and acknowledged. Sull we 
close the pages of the “ Siluria” feeling quite as deeply that if 
much has been done, much more remains to do; the outlines 
have been drawn upon the canvass, but the perfect picture will 
only be the result of long-continued and associated labor. 
geologists of this country especially have a noble task before 
them ; their field is almost unlimited, the results must be pro- 
Portionally grand.—zs. D. w. en 
Arr. XXXVIII.—Barometric Anomalies about the Andes ; by 
. Lieut. M. F. Maury, U.S. N.* 
Lievr. Herxpoy, U.S. N., in his descent of the Andes, in 
1851-52, on his way from Lima to explore the valley of the Ama- 
zon and to descend that river to the Atlantic, determined the 
heights of various places above the level oS the aa ety baro- 
metric pressure, and by the boiling point of water. 14s boiling ap- 
paratus was piinatriched by Mr. Wn. Wurdemann, of Washington. 
His observations as to atmospheric pressure, made with the 
View of determining heights above the sea level, appear to indicate 
Ls Oe trom Manry's-Sailing Directions; 4to, 1853. 
Szconp Sznms, Vol, XIX, No. 57.—May, 1855. 49 
