Review of Recent Geological Literature. 47 
Chalmers, seem yet to be wholly consistent with Hitchcock's observa- 
tions of southeastward glaciation and drift transyjortation across Maine 
and the White mountains, doubtless part of a continuous southeast 
outflow from the Laurentide highlands, belonging to the time of maxi- 
mum glaciation and indeed probably to the greater part of the Ice age. 
Furthermore, Chalmers' conclusions for New Brunswick and Nova 
Scotia are likewise consistent with the reviewer's opinion that a great 
glacial lake (named the lake St. Lawrence) was formed during the clos- 
ing stage of the Glacial period by the northeastward recession of the 
ice-sheet, extending in the St. Lawrence basin from Ottawa to Quebec 
or beyond, previous to the invasion of that area by the sea when the 
ice barrier was at last melted through. 
During the culmination of the Glacial period, the highest part of the 
ice-sheet, above the St. Lawrence basin, was probably on the north side 
of the Adirondack mountains ; but when the final melting was far 
advanced, the summit of the ice on the belt whence it outflowed both 
westward and eastward in the St. Lawrence valley appears to have 
migrated until its latest blockade was near Quebec, which is more than 
100 miles west of New Brunswick, being on the same meridian as the 
boundary between Maine and New Hampshire. A large tract of the 
ice-sheet on northern New England and yjart of New Brunswick prob- 
ably remained un melted until after the ice had vanished along all this 
valley, so that subsequent glacial outflow from the Green and White 
mountains doubtless radiated for a short time in all directions, the ice 
motion being reversed on the north from its early and chief southerly 
course during the main part of the Glacial period. The southwestward 
striation and transportation of drift in the St. Lawrence valley west- 
ward from Quebec belonged thus to a much later time than the south- 
eastward movement over the mountains of New England ; but both 
preceded the scanty northward dispersal of boulders in the country 
south of the St. Lawrence river. w. u. 
Las Rocas Eruptives de Surveste de la Cuenca de Mexico. By 
EzKQuiEL Ordonez. (Bulletin of the Geological Institute of Mexico, 
no. 2, 46 pp., 1895.) This work is composed of two parts, in the first 
of which the author reviews in a general way the more salient geo- 
graphical features of the valley of Mexico and gives a brief description 
of its geology, showing the genetic relations of the eruptive rocks. The 
distribution of each different class of rocks is touched upon, all of them 
belonging to the modern volcanic series ; the first which have made 
their appearance are the trachites, followed by the andesites, labrador- 
ites, and last of all the basalts. The author also gives a succinct 
account of the basaltic volcanoes in the south region of the valley, 
which volcanoes have in past time sent forth large quantities of lava and 
cinders. One of these volcanoes, called Xitli, has prodviced a bed of 
lava about 12 kilometers in length and six in breadth : judging from 
the human remains and articles of industry found therein, the eruption 
must have taken place quite recently, although modern history makes 
no mention of it. 
