EXPLANATION OF PLATE I.1

FIG. 1. Section at Slaughter Pen Bluff, at the head of Cross Lake, one-half mile above Shreveport. (Reduced from figure in L. C. Johnson's Iron Regions of Louisiana and Texas, p. 18.) This section probably is Lignitic.

FIG. 2. Section of Lower Claiborne on Hammetts Branch, SW. sec. 30, T. 18 N., R. 6 W., 2 miles northeast of Mount Lebanon. No. 1 grades into 2, and 5 is derived from 6 by oxidation.

FIG. 3. Section of Lower Claiborne in the first railroad cutting west of Arcadia. Length of cutting, 1,040 feet; depth, 15 feet.

1. Red clay with some sand passing into

2. Gray laminated clay ("Arcadia clays") passing into

3. Black, thinly laminated clay.

FIG. 4. Section of Lower Claiborne 6 and Northwestern Railway.

miles south of Gibbsland, on the Louisiana

Length of cutting, 510 feet; depth, 163 feet.

1. Red clay, with some sand in the upper portion, passing into
2. Gray laminated clay ("Arcadia clays") passing into

3. Black, thinly laminated clay.

FIG. 5. Section of Lower Claiborne one-half mile north of Natchitoches, on Old River. No. 1 is a yellow calcareous marl with calcareous nodules, forming a prairie soil. Ostrea sellæformis and an Orbitulina-like foraminifer are very abundant in many places on the surface. Below the surface a few feet sometimes fossils are numerous; sometimes only calcareous nodules are present.

Below the lignite seam (3) the laminated sands and clays sometimes show cross bedding.

FIG. 6. Section of bluff on Saline Bayou one-half mile above St. Maurice, showing

fossiliferous Lower Claiborne (4), overlaid by the Cocksfield Ferry beds (2). I do not know whether 3 should be referred to the same category as 4 or classed with 2. The whole section, excepting 1, is one conformable series. No. 1 is gravel, probably of Columbia age.

FIG 7. Section at Cocksfield Ferry, showing the Cocksfield Ferry beds, lower part of section unexposed. No. 1 is gravel, probably of Columbia age.

FIG. 8. Section near the upper end of the bluff at Montgomery showing the Jackson 2, 3, and 4 overlying the Cocksfield Ferry beds 6 and 7.

FIG. 9. Section one-half mile west of Provencal, on the Texas and Pacific Railway, showing what is probably the basal contact of the Sparta sands. Cutting 240 feet long, & ce deep.

1. Yellowish sand with some clays, resting uncomformably on

2. Stratified red clay with white clay partings, mantled by soil 2', probably Eocene.

3. Hematitic iron ore developed along the contact of 1 and 2.

Sections drawn by D. W. Cronin.

This plate is the same as pl. ix in vol. xv of the American Geologist, 1895.