Eughan.] LOWER CRETACEOUS FORMATIONS. 17 
Scaphites ? sp., several small distorted specimens that may be Olcostephanus 
or some other ammonoid genus. 
Turrilites brazoensis Roemer. 
Nautilus texanus Shumard. 
DEL EIO CLAYS. 
The top of the breaks of the Rio Grande to the northeast, east, and 
lutheast of Del Rio is formed of the Biida limestone, to be dis- 
tssed later. The slope is composed of the Del Rio clays. Within 
le breaks near Del Rio, to the southeast, is a conical-shaped butte, 
ailed Lone Hill, also composed of these clays, and they are exposed 
miles west of Brackett, on the road to Del Rio, where they are over- 
dn by the Buda limestone. 
The following- is a section exposed at the old ocher mine 2 miles 
orth of east of the Del Rio court-house: 
Section at ocher mine °2 miles north of east of Del Rio court-house. 
Buda limestone capping. Feet. 
Slope to the edge of the bluff covered with Exogyra arietina, a few feet. 
Yellowish clay 15 
Red clay 1 5 
Thin indurated sandy layer £ 
Red clay 10 
Greenish clays 30 
In the lowest stratum are thin, sandy flags containing Equisetum? 
id Nodosaria texana. Exogyra arietina is very abundant throughout 
e section. No. 4 is the bed from which the red ocher has been 
mod. This ocher is usually a vermilion-colored clay. 
The section above described illustrates the lithologic characters of 
e beds. At the base, along the contact with the Fort Worth lime- 
)ne, there is a white calcareous clay. Above this bed the clays are 
gaily greenish before weathering. When subjected to atmospheric 
Bon they become yellowish. Beds of red clay occur near the top. 
equently the Exogyra arietina is cemented into slabs by a sandy 
•ruginous matrix. The thickness, as determined by the aneroid 
gometer, is 100 foot. 
Although fossils are numerous in these clays, there are but few 
feies. The following are the species collected and the localities 
ence they were obtained: 
Fossils from, 20 mil ex west <>f Brackett. 
Nodosaria texana Conrad. 
Pecten, a small undescribed species. 
msilsfrom old ocher mine on bluff '2 /idles north of east of Del Rio cowrt-house. 
Nodosaria texaua Conrad. 
Exogyra arietina Roemer. 
Plicatula incongrua Conrad. 
Neithea sp., fragments. 
Esquisetum? 
Bull. 164 2 
