532 General Notes. [ August, 
nary percolating waters, which are not necessarily hot. The 
minerals and fragments of the first class, I find, fall into two divi- 
sions in the volcanic rocks: 1. Those that are characteristic of 
the rock species, and which were probably derived from the re- 
fusion of this species, that had crystallized at the depth at which 
it was prior to the eruption; 2. Those that are accidental, proba- 
bly caught in the passage upward or during the outflow. ‘Similar 
divisions are found, to a greater or less extent, in the sedimentary 
rocks, according as they were derived from one or more rocks, 
and also according to the preponderance of different rock frag- 
ments and minerals in them. Details of these occurrences will 
be given in the final publication. 
“ Believing that new names should not be employed, except in 
cases of absolute necessity for filling gaps in the classification, 
the effort has been made to retain all the old names that are nec- 
essary, in their most es use, and to reject all needless ones, 
that can be so dealt wi 
“Starting with the Banc rocks, I shall pass from the glassy 
states to the most crystalline, from the least altered to the most 
altered, and from the massive to the clastic, keeping on a similar 
range of chemical composition, and tracing the various gradations. 
step by step. I shall also, in like manner, trace the gradations 
necessities of the case, both in the use of these observations in a 
thesis and in giving a post-graduate course in lithology in this 
Museum, my work was made public before it was entirely com- 
pleted, it has been deemed necessary to publish this abstract in 
advance. Several matters of detail yet remain to be worked out, 
which may modify some of the general views. All that is liable 
to be so modified must, therefore, be withheld for the present.” 
GEOLOGICAL AND PALHONTOLOGICAL News.—M. Mariano Bar- 
- cena continues his researches on the geology and paleontology of 
Mexico in the Anales del useo Nacion al de Me xico. —Dr. 
nodon, Titanosaurus indicus, Plesiosaurus, etc. Dr. Lydekker in 
another paper describes an extinct Quadrumane from the Sewaliks 
of enian, of rather larger size than the orang outang, which he 
names Palæopithecus sivalensis. r. C. D. Walcott of Albany, 
tt Y., continues his researches on the structure of the Moss ar 
us an account of the metamorphoses of Triarthru. 
becki of the Trenton limestone. He also discusses the Utica stole 
and its fossils ——The Rev. W. H. Barris publishes in the proceed- 
ings of the Davenport Academy of Sciences an account of the 
, local geology of el ie Iowa, and describes some new Cor- 
a  niferous fossils. 
