228 The American Geologist. October, 1896 
lu the ensuing- diBcussion, Prof. G. F. Wright and Mr. (i. K. (iih- 
BERT concurred with the jiuthor's conclusions. 
IS. The Makimj of M(U)im<)tli Cave. Horace C. Hovky. The bibli- 
ography of the Mammoth ('ave of Kentucky includes more than four 
hundred citations, and many of the authors and observers ascribe the 
origin of the cave to earthquakes aided by the grindingagency of whirl- 
ing water freighted with sand and pebbles. This latter theory for the 
formation of the pits and domes is held by Dawkins and Shaler, as well 
as others of note. The present author, on the contrary, after having 
examined every pit and dome in this immense cavern, believes that they 
were all made by solution and decomposition. The limestone from 
which the cave was excavated shows slight signs of seismic disturbance; 
and the streams have accomplished little through abrasion or erosion. 
In company with Dr. R. E. Call, the author has measured nearly all 
the large pits and domes, in gathering details for a new guide-book of 
the cave. The Bottomless Pit is 105 feet deep. Gorin's dome is 105 
feet deep from the top, and 88 feet from the "window," where tourists 
usually look into it. Garvin's pit is 95 feet deep; and Scylla and Cha- 
rybdis are 89 feet deep. The Maelstrom is 98 feet deep. These meas- 
urements were taken with the utmost care and can be relied upon as 
correct. 
19. The Colossal Cavern. Horace C. Hovev. There are said to be 
five hundred caverns in Edmonson county, Kentucky, so that the find- 
ing of a new cave in that region need not surprise anyone. But the 
Colossal Cavern, discovered in July, 1895, by Mr. Pike Chapman and 
owned by Mr. Hazen W. Proctor, is really a great discovery. It is onlj' 
about four miles from the Mammoth Cave, which it resembles in many 
of its features. The entrance, however, is down through an orifice at 
the top of a dome. After descending Q£i feet, the Vjottom is found to be 
a mass of debris. Thus the visitor descends dome after dome, by means 
of ladders, until he stands at a point 240 feet below the place of en- 
trance. These domes are very magnificent. The crystal rosettes (ou- 
lopholites) are extraordinarily delicate and superb. Never having been 
disfigured or blackened by torches, they are white as snow and sparkle 
brilliantly under the magnesium light. There is said to be a large body 
of water in this cave. Explorations by strangers are not allowed, as the 
effort is being made to find some more convenient way of access through 
some other known cavern. 
20. James Hall, Founder of American StraligrapJiic Geoloyi/. W J 
McGee. 
•^1. Professor Hall and the Survey of the Fourth District. John M. 
Clarke. 
22. Sheet flood Erosion. W J McGee. Papagueria (the land of the 
Papago Indians), lying in southwestern Arizona and western Sonora, is 
a distinct province or subprovince presenting many interesting geologic 
and geographic features. It is hot and arid; its waterways are few and. 
small and never reach the sea, so that degradation and aggradation are 
i'omplete within it; it is an area of broad, undulating plains, separated 
