CURRENT PRE-CAMBRIAN LITERATURE 849 
occupy but a small proportion of the pre-Cambrian area, the sedimen- 
taties are not mapped as Algonkian, but, with the granites, are mapped 
as pre-Cambrian. 
Osann’ gives the geology and petrography of the Apache (Davis) 
mountains of western Texas. The oldest rocks found therein are 
the crystalline schists, which composed the greater part of Carrizo 
and Van Horn mountains. Here is found a great set of coarsely crys- 
talline gneiss, mica-schist, and associated schistose rocks. ‘These have 
in general a parallel northwest-southeast strike, which agrees with the 
axis of the range. Following Professor von Streeruwitz, these are 
placed with the fundamental rocks. 
Sapper? describes the geology of Chiapas, Tabasco, and the Penin- 
sula of Yucatan, and mentions the occurrence of Azoic rocks in the 
Sierra Madre Mountains. ‘These rocks include gneiss, mica-slates, and 
phyllites. A band in the first northern range of the Sierra, near the 
plantations of Piedad and San Vincente, trends N. 7° W., and dips 5° 
to the N.E. Among the bowlders washed down by the Aguacate River 
may be seen gneiss, mica-slates, and phyllites, which indicate the 
presence of the crystalline formations also in the interior of the Sierra 
Madre. 
Comment.— The term Azoic is used in a very indefinite way. It 
apparently is applied to all ancient crystallines, both sedimentary and 
igneous, and is not necessarily confined to the pre-Cambrian. How- 
ever, the term is placed as a subheading under sedimentary formations, 
indicating, possibly, that ancient sedimentaries only are included. 
Ells’ reports on the geology of a portion of the Province of Quebec 
comprised in the southwest sheet of the eastern townships map (Mon- 
treal sheet), and describes pre-Cambrian rocks occurring to the east of 
the St. Lawrence River. These occur along the axis of the Sutton 
‘Beitrige zur Geologie und Petrographie der Apache (Davis) Mts., West-Texas, 
by A. OSANN. Min. und Pet. Mitt., Bd. XV, Heft 5, 6, 1896, pp. 394-456, mit Tafeln 
XI-XII, Fig. im Texte. 
2 Geology of Chiapas, Tabasco, and the Peninsula of Yucatan, by C. SAPPER. 
Jour. GEOL., Vol. IV, pp. 938-947, 1896. 
3 Report on a portion of the Province of Quebec, comprised in the southwest sheet 
of the “Eastern Townships” map (Montreal sheet), by R. W. ELts. Ann, Rept. 
Geol. Surv. of Canada, for 1894, Vol. VII, Part J, 1896, pp. I-92. 
