Correspondence. 267 
suggests that their production may be the result of the hydrostatic pres- 
sure of the sea water lying above the deposits. In the instances examined 
stylolites are characteristic of marine deposits formed in water varying 
from 400 to 2500 fathoms in depth. If cea water be taken to have an av- 
erage specific gravity of 1.028, then a one-foot column of water exerts 
a hydraulic pressure of .434 lb. per sq. in. of area. This would give, for 
the depth stated, a hydrostatic pressure of from 1041 to 6408 lbs. per sq. 
in. Such a pressure as this, coupled with the soft unconsolidated nature 
of the rock at the time it might have been exerted, seems to fulfill better 
than any other the conditions demanded by the observed facts. 
''Recent Journeys Among Localities Noted for the Discovery of Re- 
mains of Prehistoric Man," by J. Hozvard Wilsan. The author discussed 
man in the earliest times before the neolithic age and afterwards illus- 
trated his paper by nearly forty views oi some of the most famous rdck 
shelters, caves and deposits of Europe which have furnished remains of 
palaeolithic man, including also slides oX the type implements and wea- 
pons from which is derived the principal evidence of man's existence in 
Quaternary times. 
The paper recited briefly the history of the subject, the first finds, es- 
pecially the work of Boucher de Perthes, and the gradual development of 
the science of prehistoric archaeology. Reference was made to some of 
the disputed evidence of man's existencv; in the Tertiary period, and then 
the subject of man's undoubted existence as early as the Second Glacial 
period was treated more at length, with a consideration of the climate 
and physical conditions which prevailed in Palseolithic times. 
The paper closed with an attempt at a realization of the great an- 
tiquity of pateolothic man as shown by the immense physical and geolog- 
ical changes which have taken place since he first made his undoubted 
appearance. 
At the regular meeting, February 15, vice-president James F. Kemp 
presiding, the secretary read a letter from Dr. J. G. Aguilera correcting 
a statement in one of the papers presented at the December meeting 
of the Academy, as reported in Science, regarding the great Bacubirito 
meteorite of Mexico. Dr. Aguilera called attention to the fact that this 
meteorite was discovered in July, 1871, as was stated by A. del Castillo 
in Catalogue descriptif des Meteorites, Paris, 1889. It was described by 
F. Sosa y Avila in Minero Mexicano in 1890, and afterward was visited 
by Signor Buelna as a commissioner of the Geological Institute of Mex- 
ico for the purpose of calculating the cost of transporting it to the city 
of Mexico. In connection with this expedition Buelna made several 
drawings and photographs of the great mass of iron. Through the Geo- 
logical Institute professor H. A. Ward received exact information as to 
the locality of the meteorite and then visited it, removing the earth from 
about it and making new photographs. Professor Ward's recent articles 
(1Q03) have drawn renewed attention to this enormous meteoric mass, 
but the credit of original discovery and description belongs to the Mex- 
icans. 
