A PRELIMINARY REPORT ON THE AUSTIN CHALK 
UNDERLYING WACO, TEXAS, AND THE 
ADJOINING TERRITORY. 
JOHN K. PRATHER, B. S„ 
Waco, Texas. i 
Prof. Eobt. T. Hill, of the United States Geological Survey, gives the 
following divisions of the Upper Cretaceons: (1) Navarro formation; 
(2) Taylor formation; (3) Austin chalk; (4) Eagle Ford shale; (5) 
Woodbine or Dakota formation. 
As early as 1845, Dr. Ferdinand von Koemer spent some time in 
studying the Cretaceous formations of Texas, and nearly all thu fossils^ 
from the Austin chalk with which we are familiar were studied and 
described by him. Among those best known are the following' inverte- 
brates: * Hernia ster texanus, Eoemer; Ammonites (Mortoniceras) tex- 
anus, Eoemer; Terrebratella guadalupse, Eoemer; Ammonites dentato 
carinatus, Eoemer; Eadiolites austinensis, Eoemer; Scaphites (species 
not determined); Gryphsea aucella, Eoemer; many nautiloids; Inoee- 
ramus deformis, Meek and Hayden; Inoceramus undulato-plicatus, 
Eoemer; Spondylu's gaudalupae( ?), Eoemer; Pectens; Baculites asper 
(?) Morton — but of a much larger size than is usual in that species; 
Inoceramus confertim annulatus, Eoemer; Inoceramus exogyroides, 
Meek and Hayden. Concerning the last-named species, Dr. T. W. Stan- 
ton says : “I had not seen this species before from Texas, although I 
believe it has been reported from the State. It was originally described 
from the Missouri river, near Fort Benton, Montana.” Among the ver- 
tebrates are found the remains of such animals as Clidastes, Squalidonts, 
Cestracionts, and many others. 
A paleontologist will find this a very fruitful field for investigation. 
The main difficulty to be encountered in the study of the fossils is that 
so many are^ either casts or are so fragile that they break in pieces in 
getting them out. Many of the invertebrates are so large that they are 
both hard to collect and difficult to transport. 
The Austin chalk is the most characteristic of the Cretaceous forma- 
tions. It is a massive stratified limestone with white and blue layers of 
different thicknesses. Sometimes the white and blue layers alternate, in 
other places there is a horizon of white followed by one of blue. Good 
lime can be made from it, but the Edwards limestone is better suited 
for lime-making and for building stone. The strata vary in thickness 
from 4 inches to 8 feet; but are rarely less than 1 foot, and are generally 
1 \ and 2 feet thick, The separating material, where found, is marl, 
