1.{Quartzites and clay slates;
{Black, jaspery schistose layers;
or, where the rocks are less altered:
{Black clay shales with beds of coal;
{Argillaceous sandstones.
2.Quartzites, in great thickness.
3.Heavy beds of conglomerate.

The interstratified clay shales and grits of the lower member, crop out in several places along the Cañada de Santa Maria, at the bottom of the ravines below Los Bronces. Here, there are three or four beds of good anthracite coal, with a considerable number of well-preserved plants occurring in the associated clay shales, both above and below the coal.

[A portion of these plants were referred by me to Dr. Newberry for examination, and he has given the following list of them. 1. Strangerites magnifolia, Rogers; Trans. Assoc. Am. Geologists, p. 306, Pl. xiv. A species occurring in the Trias (?) of Virginia and North Carolina. 2. Pecopteris falcatus, Emmons; Geol. of N. Car., Pl. iv, fig. 9. The specimens are too imperfect to decide on the identity of this plant with Saccopteris germinans. ?3. Pecopteris bullatus, Bunbury; only in fruit; nervation obscure; identity not certain, but very probable. 4. Otozamites Macombii, Newb. At top of “red beds” or “gypsum formation,” at the base of the Cretaceous rocks, copper mines near Abiquiu, New Mexico. There is no doubt about this species, and it forms an important connecting link. ?5. Pterozamites decussatus, Emmons; specimens very imperfect. 6. Pecopteris, n. sp.; a very neat and peculiar species as yet undescribed. It may be the same as one badly figured by Emmons (Pl. II, fig. 1.) 7. Alethopteris, n. sp.; small fragments of the frond of a splendid new species. From this enumeration it will be seen that there can be but little doubt of the Triassic age of the formation in which these plants occur. A large lot of these plants, collected by M. Rémond, has been recently received, and among them are much better specimens of some of the species noticed by Dr. Newberry, and several quite new ones. These will also be examined, described, and figured within a short time. J. D. W.]

The strike and dip of the clay shales in the different ravines vary considerably, but the dip is usually to the southeast. The superincumbent quartzites are more regular in their inclination. There are dykes of feldspathic rock cutting through both the coal and the shales.

The following section represents, in an ascending order, the position of the coal-bearing strata in the Cañon del Retiro, near Los Bronces.

Another section, measured at the foot of the Cerro de la Aguja, was as follows.

[Specimens of the coal brought to San Francisco by M. Rémond, are anthracite, evidently of superior quality. J. D. W.]

The middle member of the Triassic series consists of quartzites, or metamorphic sandstones; these are both coarse and fine grained, and sometimes brecciated. They vary in color, from white to red, and are often much altered in the vicinity of the metalliferous veins. The upper member of the series, as seen in the Cañada de la Tinta, is made up of rounded pebbles of black jasper and gray quartzite; in the Cañada de los Mimbres, below Los Bronces pebbles of specular iron are included in the mass. The dip of the formation is very irregular, both in direction and amount.