, VAUGHAN.j EOCENE FORMATIONS. 39 
list of the species found there. Harris (op. cit., loc. cit.) says: * * * 
"we should note the peculiar fauna, Midway, in part, at least, found 
by Dr. White 18 miles southeast of Eagle £ass. It consists of Cucul- 
Icea macrodo?ita (perhaps saffordi), Pectunculus, Venericardia [pi. 5, 
fig. 3], 'The shelly matter of these species is completely crystallized.' 
'The matrix was evidently a calcareous light sand or sandstone.' 
Harris, Ann. Rept. Geol. Surv. Ark., 1892, Vol. II." 
The actual Cretaceous-Eocene contact has not been located along the 
Rio Grande. 
It has been reported that many fossil oysters occur on the high 
divide between the Chupadero and India ranches, west of San Ambrosia 
Creek. The writer was unable to make a search for the locality, and 
did not learn of anyone who had collected specimens from there. He 
is of the opinion that the section referred to is a bed of Ostrea crenuli- 
marginata Gabb, as this species occurs at several places in the basal 
Eocene of Texas. 
The following section l of Webb bluff, on the Rio Grande, 3 miles 
below the north line of Webb County and southeast of India ranch, 
is from Penrose: 
Section of Webb bluff, on Rio Grande. 
Feet. 
3. Fine, white, indurated, sandy clay, with dark streaks and specks of lignitic 
matter 30 
2. Greensand marl, with many Tertiary fossils, nodules of carbonate of lime 
containing glauconitic specks 7-8 
1. Stiff, plastic, bluish-black clay, jointed, containing specks of mica 10 
Dip of strata, 3° SE. 
Durable subsequently published the same section 2 and stated that it 
is capped by gravel. Beds Nos. 2 and 3 are the same as the Webb 
bluff beds of the section by Dumble. 
The coarse-grained sandstone seen around Chupadero ranch is over- 
lain near there by a finer-grained laminated sandstone. At Guajolote 
ranch the coarse-grained sandstone has disappeared, and we have the 
following section: 
Section at Guajolote ranch. 
Ft. in. 
6. Gravel capping (Pleistocene) . 
5. Micaceous shale 10 
4. I .edge of brownish-green micaceous sandstone 2 
3. Laminated micaceous sandstone - . . 8 
2. Seam of ferruginous concretions 3 
1. Massive yellow micaceous sandstone, thickness unknown. 
1 First Ann. Rept. Geol. Survey of Texas, 1890, p, 41. 
2 Bull. Geol. Soc. America, Vol III, 1892, p. 228; also, Dumble's Report on brown coal and lignite of 
Texas. Geol. Survey of Texas. 1892, p. 137. In the latter report it is stated that the lowest stratum 
is Cretaceous. 
