On Baciibirifo. — ll'ard. 209 
latter case it seems probable that some of the soil should have 
been caught and held between the meteorite and its bed. A 
good deal to our surprise we found that this bed was a clean 
depression crushed into the rock with absolutely no trace cf 
soil between it and the part where the full weight of the 
mass had fallen and lain. It would thus scciii tliat the mete- 
orite had fallen on the bare surface of this district at a period 
before the vegetable soil had begun to form here. This would 
be an interesting and astounding fact, carr}-ing back the fall 
of our meteor to a remotely distant period, pf^rhaps thousands 
of years. But there are other conditions which would need 
careful consideration before accepting such a momentous con- 
clusion. 
The wonderful preservation of the mas'?, with its little 
oxydation and the clean, sharp-rimmed pitting-s which cover 
its surface, seem to point to a more modern sojourn within 
the destroying influences of our air and moisture. We leave 
this for future consideration. 
It is an interesting fact that this, the largest and probably 
the heaviest meteorite mass yet discovered on our globe, 
should have fallen so near the present border of our own coun- 
try. Interesting, too, that Mexico with all its other extra large 
meteorites should have received this champion mass. 
The extreme measures of Bacubirito, for so our meteorite 
from the first has been called, are : — 
Length, 13 feet and i inch. 
Width, 6 feet and 2 inches. 
Thickness, 5 feet and 4 inches. 
Its form, as shown by the photographs, is extremely irreg- 
ular, and though measures have been taken ?^-round the mass 
at many different points, its cul)ic contents cannot be calculat- 
ed with more than an approximation to accuracy. 
The five largest meteorites known to science today are : — 
Bemdego (Brazil) 51-3 tons. 
San Gregorio (Mexico) 11 1-2 tons. 
Chupaderos (Mexico) 15 2-3 tons. 
Anighito (Greenland) 50 tons. 
Bacubirito (Mexico) 50 tons. 
The first three are weights proven on scales The last 
two are tluis far simple estimates. How far estimated 
