286 Recent Literature. [ April, 
but his examinations were rather cursory. This mountain, with 
others farther to the east, were carefully studied by Mr. i 
Holmes, of the Hayden Survey, in 1875 and 1876, and his illus- 
trations in the reports for those years show the same structure in 
the La Plata mountains, the Sierra Carrisso, and the Sierra El 
Late, in South-western Colorado and adjacent regions, with some 
points that do not appear in the Henry mountains, probably on 
account of the greater simplicity of the latter. . Fi ; 
ings appear to be nearer to nature, z.¢., less schematic. Scattered 
through Hayden’s reports from 1873 to 1876 are many descrip- 
tions of this type of structure, and the term Porphyritic-Trachyte 
(p. 64 and 68) used by Mr. Gilbert to designate the group to 
which the rocks belong, was first used by Dr. A. C. Peale, of 
Hayden’s corps, in 1874 (see his report for 1874 in Hayden’s An- 
nual Report), and afterwards he always used the term in designa- 
ting the rocks. 
Mr. Clarence King, in his report (Systematic Geology, 1878, 
p- 581), proposes the name Trachytoid-porphyry for the group, 
having recognized the resemblance of certain rocks occurring 
within the area of his explorations, to those of the Henry moun- 
tains. Healso recognizes the peculiar petrographical position 
of the rocks, one extreme of which cannot be distinguished from 
granite, and the other of which is undoubtedly trachyte. This 
fact was also pointed out by Dr. Peale in 1874 and 1875 (see his 
reports to Dr. Hayden). The descriptions of the localities men- 
tioned in Dr. Hayden’s Annual Reports were brought together 
in an article (On a peculiar type of Eruptive Mountains in Colo- 
rado) in Bulletin No. 3, Vol. 11, of the U. S. Geological Survey 
of the Territories, published May 15, 1877. Mr. Gilbert’s vol- 
ume is dated Washington, 1877, although it was not published 
until about four months ago. 
BATRACHOLOGICAL PAPERS.— Prof. Peters, of Berlin, has recently 
published an important paper in the Berlin Monatsberichte,’ on 
the Ceciliide. He discovered two new generic forms in which the 
usual position of the orbit is covered over by the squamosal bone, 
thus enclosing the rudimental eye in the fundus of the tentacular 
canal. One of these, Gymnopis, is American; the other, Herpele, 
trema was proposed on an immature Ichthyophis. 
paper Prof. Peters? describes two new species of Gidipus, one 
nopis u. Rhinatrema, 
2 Monatsherichte Berliner Akademie, August, 1879. 
mes’ draw-: 
1 Ueber die Eintheilung der Cecilien, und insbesondere ueber die Gattungen Gym- 
ren Nov., ` F 
