TJie Geological Society of America. — Hovcy. 99 
cliff, they found a mortar lodged forty feet below the surface, a pestle 
twenty feet lower still, and nearby another mortar on the bed-rock. 
all manifestly fallen from above. During their work, they had been 
compelled to recognize a considerable number of possible sources of 
error, with respect to association, against which early observers had 
not guarded. The communication concluded with the explanation 
that the investigation was not yet complete, but that it would be 
continued along each of several special lines, all tending to elucidate 
the archeology of California. 
In the ensuing discussion, professor W. H. Brewer and professor 
S. F. Emmons raised questions concerning the alleged fossilization 
of the Calaveras skull, which the authors were not in position to 
answer, pending examination of the specimen; though they mention- 
ed finding partially calcified Indian crania from caverns in the vi- 
cinity, where the Miwuhk Indians frequently dispose of their dead 
by casting them into the deepest caverns they are able to find. Major 
Powell noted the untrustworthy character of the testimony of un- 
scientific men as to associations, instancing the Nampa figurine, al- 
leged to have been found under the Tertiary lava sheet in Idaho, 
which a well-operator sought to palm off on him as a genuine dis- 
covery, and which was afterward actually foisted on a credulous col- 
lector, and published as evidence of high human antiquity. Professor 
J. A. Holmes described the discovery of an object, in Miocene de- 
posits of the Coastal plain, which was attested to be in place in the 
undisturbed formation by afifidavits of all finders, including the army 
officer in charge of the work; the object proving, on examination, to 
be a piece of a revolver of rather recent make. 
One of the most interesting statements brought out by the 
discussion of this important paper was that of major Powell, 
that most, if not all, of the European claims to the great an- 
tiquity of man rest on evidence that is of a character analogous 
to that of the Calaveras skull, in the sense that it all has yet to 
be stibjected to expert re-examination. 
C. 1). Walcott, director of the U. S. Geological Survey, 
made the important and rather startHng announcement that 
during the past season he had discovered indisputable fossils 
in the Algonkian beds of Montana, about 4,000 feet below the 
base of the Cambrian. The remains consist of separated 
plates of crustaceans closely related to Eurypterus. Several 
specimens were exhibited by the speaker, and the fossiliferous 
horizon was stated to be about 80 feet in thickness. 
" A)i Unreco'j^nized Process in Glacial Erosion," by WlL- 
i-.^RD I). JoHN,soN, U. S. geological survey. The glacial 
t()pograi)hy of mountains was analyzed, and the more distinctive 
