920 General Notes, [September $ 
bulb of a withered and somewhat irregular and variable shape | 
De Koninck, in his magnificent work upon the “ Calcaire Carbon- 
ifere de Belgique,” curiously enough cites these very forms as the | 
principal proofs against my conclusion, because in them the sta 
is absent. According to my examinations and drawings, howevt, 
the scar ought to be found in such examples underneath the bul | 
of the apparently complete apex, which is simply the withered | 
and shrunken remains of the primitive protoconch. This was 
evidently originally a soft, embryonic shell, composed of conch 
olin, and not of calcareous matter as in the Ammonoidea | 
have seen and figured several examples in which a bulb ws f 
present on the apex and no scar visible, and onecase in which the 
bulb (protoconch), had evidently been taken away, leaving tht 
scar visible below, surrounded by the broken edges of the outer 
most shell layer, which formerly connected the apex with, and 
covered the protoconch, The external layer of shell and its 
longitudinal ridges from the apex up, on to the so-called plug 
the cicatrix described by Barrande, have also been traced, - 
thus every point in the evidence appears to be complete, and the 
fact that the bulb is covered bya true protoconch continuous 
with the shell of the apex seems to be established.—Alpheus Hyatt. 
Fossit Man in Mexico.—Dr. Mariano Barcena, director id 
department of Geology and Palzontology of the National hi 
seum of Mexico, recently discovered the facial and mandibu 
parts of a human skull in a hard rock not far from the city : 
Mexico. The specimen was found in a hard siliceous lime the 
near the border of Lake Texcoco, at some elevation above a 
level of the water of the lake. Overlying the bed of ene 8 
is a lacustrine deposit, which is similar to that made by the m 
ent lake, and contains the same mollusca, etc. W ae 
limestone be a still more ancient deposit of the lake, has not yi 
been determined by Dr. Barcena, but the overly ing depa a 
cates the former wider extension of its waters. It is also €v! its 
that since the entombment. of the human skull, both ian 
have been elevated several feet, and separated from the aet od “ 
under the lake by a fault. This was probably accomplis y 
the time of the projection of an eruptive hill near the i 
GEOLOGY oF ALGIERS.— Tertiary —The three tertiary, me 
say M. Peron, can usually be easily distinguished in Ape "The © 
they present themselves in isolated and independent Sardinia, and 
systems of upheaval of the Pyrenees of Corsica and Sar l jers, 
of the western Alps, have all played an important part 1n, pe 
and have so separated the tertiary areas as to render me i 
fication relatively easy. The eocene is in many places â 
without fossils, and in most others offers nothing to the 
