Correspondence, 1 99 
beach is much more mature, but it hes nearly parallel with the contours 
of a comparatively smooth sloping plain, and the conditions favored 
the rapid maturing of the shore line. Eastward from Indian Falls the 
land surface is very uneven and the shore line lies transverse to the 
drumlin molding, which conditions would require a much longer time 
to straighten and mature the beach. With all allowances, the impres- 
sion made upon the mind is that of somewhat less duration of the 
beach-making forces in the Genesee region." 
With any criticism of my work which brings out more refined de- 
terminations than I have made I am in full sympathy. The studies by 
Prof. Fairchild, Mr. Upham, and Mr. Taylor, just noted, have all been 
helpful to a better understanding of the situation. No doubt as the 
work continues much more refined and delicate discriminations will be- 
come possible. Faith in the harmony of the universe inspires confi- 
dence that the features of debatable origin, in which Dr. Spencer has 
taken refuge as a defense against glacial dams (page 117) and which 
have as yet received less attention than they merit, will some time be 
found consistent with the already well established facts and principles 
of geology, among which facts it seems safe to include glacial dams. 
Opportunity is here taken to state that, in presenting the name Crit- 
tenden for the principal beach of lake Warren, I had no intention of de- 
parting from the usage of naturalists, as intimated by Dr. Spencer (page 
119). For I doubted its being the precise equivalent of the Forest 
beach. These doubts have in a measure been removed upon discussing 
the matter with Dr. Spencer. Although continuous tracing has not as 
A^et been made, there seems little question that the Crittenden beach 
is the equivalent of the Forest. Such being the case the name Forest 
has priority. It may also be remarked that the name Belmore, sug- 
gested by Prof. N. H. Winchell, has priority over the name Ridgeway, 
suggested by Dr. Spencer. 
Denmark, Iowa, Feb. g, j8qS. Frank Leverett. 
A New Well at Rock Island, Ills. — A new well has lately been 
drilled by the Rock Island Brewing company on its premises near the 
crossing of Seventh avenue and Elm street in Rock Island, Ills. The 
curb of this well has an elevation of about 654 feet above sea level, and 
the water rose to within 44 feet of this hight. The first 100 feet of the 
hole was made twelve inches in diameter; the next 185 feet, eight 
inches; the next 240 feet, six inches; and the last 764 feet, five inches; 
the total depth of the well being 1,289 feet. There was a water-bearing 
stratum in the Trenton limestone, but the water from this rock was sul- 
phurous and was shut of? by a casing extending down to 912 feet below 
the top of the well. The drillers furnished me with a statement of the 
nature of the rocks which were penetrated. This is here given, with 
my own determinations in parentheses: 
1. "Clay, 100 feet." (Loess and till, and possibly some coal-meas- 
ure shale.) From 654 A. T. to 554 A. T. 
2. "Limestone, 30 feet." (Devonian.) From 554 to 524. 
