6 Transactions Texas Academy of Science. [120] 
(1) Soil dark, changing to a light calca- 
reous loam 18 feet. 
(2) Soft white limestone (Austin chalk).. 110 feet. 
(3) Blue shales (Eagle Ford)... 162 feet. 
This log is given in full by Prof. Robert T. Hill in his bulletin “On 
the Occurrence of Artesian and Other Underground Waters in Texas, 
Eastern New Mexico, and Indian Territory West of the 97th Meridian,” 
page 109. 
Neither at Lover’s Leap nor in the two well borings, nor at the con- 
tact with the Eagle Ford shale on Waco creek, do we find the marl 
which is spoken of by Prof. Hill as “the marl at the base of the Austin 
chalk.” In some measurements taken with, an aneroid barometer, I find 
the limestone aboVe the marl to vary in different sections, as follows : 
35 feet, 60 feet, 100 feet, and 150 feet. These measurements were taken 
at intervals of from 1 to 6 miles apart. At Lover’s Leap the whole 
thickness is not exposed, but judging from other observations here and 
at the nearest contacts with the Eagle Ford shale, there are not more 
than 20 feet unexposed. Thus it is seen that the thickness of the white 
rock (or Austin chalk) without the marl at the base, around Waco, as 
it now exists, not taking into account that which has been worn away, 
varies from 35 to 170 feet. The thickness of the marl at the base of 
the Austin chalk varies from 100 to 250 feet. 
In a section of the Austin chalk and the underlying marl, beginning 
at the top and tracing it down to the contact with the Eagle Ford shale 
below, I find the thickness to be 200 feet, as follows: 60 feet of lime- 
stone, and 140 feet of marl. The marl gives the following section : 
Marl 107 feet. 
Argillaceous limestone 2 feet. 
Marl 4 feet. 
Argillaceous limestone 1 foot. 
Marl 3 feet. 
Argillaceous limestone, in bands 2 feet. 
Marl 15 feet. 
Argillaceous limestone 6 feet. 
(This layer is composed of alternating bands of hard and soft rocks 
about 4 inches thick, containing Inocerami and Ostreae). The marl con- 
tains small pieces of gypsum, selenite crystals, and nodules of limonite. 
It is somewhat stratified, and in places turns blue on weathering. It 
contains numerous fish teeth and vertebrae, and shark’s teeth and the 
remains of a number of large vertebrates; also many Ostreae and Inoce- 
rami. The rock often weathers into thin flakes. The marl is of a clay 
yellow color. It is sometimes found without the Austin chalk, as, for 
