394 The American OeologisU June, isso 
ter. H. B. Geinitz, Geo. Isis in Dresden, 1889, Abh. 3. 
Summary Report of the operations of the Geological and Natural 
History survey, Ottawa. A. R. C. Selwyn. 
CORRESPONDENCE. 
Postscript to article on "The Maquoketa Shales." — Since the 
foregoing was put in type Mr. Leverett has kindly sent me some ad- 
ditional data of the Indiana gas borings. The following items are 
taken from his letter. 
In a well at Terre Haute, the Trenton lime-stone was reached at a 
depth of 2,860 feet or 2,400 feet below sea level. In my discussion of 
the records given in table No. 1, it is stated that a well at Terre Haute 
was carried down 2,000 feet and stopped in the Corniferous lime-stone ; 
and that if the rocks of the Cincinnati group continued to dip at the 
same rate as between Plainfield and Danville, the top of the group 
would be 1512 feet below sea level. From the later data the depth is 
even greater than this, probably 2,200 feet below sea level, if present 
at all. 
At Rockville, which is about 40 miles west of Danville and close to 
the line of section west from Richmond, (No. 1) the Trenton was about 
1,400 feet below sea level, as against 518 feet at Danville. The exact 
thickness of the Cincinnati group is not ascertained. 
Rensselaer, again, is on the direct line of the second section, drawn 
north-west from Richmond. Mr. Leverett's data from a well there 
indicates an altitude of some 70 or 100 feet for the top of the Cincinnati 
rocks above tide, and a thickness for them of 300 feet. These figures 
correspond well with the others given in my second table. 
Other well records are given by Mr. Leverett, but not being on the 
lines of section treated of, they are not mentioned here. It will be 
enough to say that the additional information confirms the deductions 
made in the body of the paper. 
Joseph F. James. 
Washington, D. C. May 5, 1890. 
PERSONAL AND SCIENTIFIC NEWS. 
The Chair of Geology and Natural History at Granville, 
0. left vacant by the call of Prof. Herrick to the corresponding 
chair in the University of Cincinnati, has been filled by Prof. 
W. G. Tight, under whose conduct the bulletin of the labora- 
tories of Denison University will be continued. The fifth vol- 
ume of this publication v^ill contain, among other geological 
papers, stratigraphical notes on the Waverly in north-central 
Ohio by W. F. Cooper, who seeks to verify and extend the 
correlations suggested for the central and southern counties 
in previous numbers. 
