* 134 Trans. Acad. Sci. of St. Louis. 
and were later especially noted by Dutton  Gilbert® 
gave the first succinct account of the Black Mesa country 
on the south. The details of the geological phenomena 
presented at Coon Butte and the vicinity are fully ex- 
plained by Foote,® Gilbert,’ Fairchild,’ Merrill,® and 
Telghman and Barringer,'® and the accounts of these 
authors reference may be made. 
Significance of Certain Geologic Features. 
Geologic Section. The drill records of borings made 
in the bottom of the Coon Butte crater are of exceptional 
interest. As given by Messrs. Barringer and Telghman 
the following section appears to be characteristic. 
Geologic Section of the Coon Crater. 
FEET 
1. Soil, sand, surface material and wash from cliffs.............. 27 
2. Lake-bed formations, lying horizontally and containing diatoms, 
shells of mollusks and abundant gypsum crystals.......... 61 
3. Sand, which gives reaction for nickel and iron, and contains 
fragments of metamorphosed sandstone, sandstone, pumice, 
OES) osu n't lain ain! tie tb le Ghali cm mae el ial le a ae is EL ae paras eee or 135 
4. Sand and rock, sand-grains crushed slightly, if any, and not 
metamorphosed, barren of meteoric material.............. 300 
5. Sand and “silica” (rock-flour), with abundant slag-iike material 
containing iron and nickel and metamorphosed sandstone.. 80 
6. Silica powder, fine (rock-fiour), and sand, no meteoric material.. 20 
7, Bed-rock, a grayish BANUStONe |. os es eto see ee twee hee 
Character of the So-called Lake-Beds. Of the several 
distinctive strata passed through in drilling numbers 2 
and 5 are of noteworthy significance; the last mentioned, 
near bed-rock, on account of being the only zone in which 
undoubted meteoric material occurs; and the first because 
of constituting the so-called lake-beds. 
4Ann. Rept. U. S. Geol. Surv. 6:113. 1885. 
5U. S. Geog. and Geol. Surv. W. 100 Merid. 3:128. 1875. 
6 Am. Jour. Sci. III. 42:413. 1891. 
™Secience, N. S. 3:1. 1896. 
8 Bull. Geol. Soc. America, 18:493. 1907. 
®Smith. Misc. Coll. 50:461. 1908. 
1 Proc. Acad. Nat. Sci. Phil. 57:861. 1906. 
