72 
THIRTEENTH REPORT. 
throughout the summer. Work in preparation of this report is being- 
pushed as rapidly as possible and it is hoped that it will be finished be- 
fore the end of 1911. 
A General Geological Map of the State. 
Tt is planned to issue a general geological map of the state on the 
black base, scale six miles to the inch, used for the soil map above 
mentioned, the same to be accompanied by a short descriptive text 
setting forth in a manner easily comprehended by the nontechnical 
reader the salient features of the general geology, including brief de- 
scriptions of the rock formations in the order in which they occur in the 
geological column, with special reference to features of economic im- 
portance. This text is designed only to render the interpretation of 
the map intelligible to the average reader. There have been received 
a large number of requests for this map from the schools and educa- 
tional institutions of the state, citizens, and from many sources outside 
the state. 
t 
Report on Earthquakes in Michigan and the Tilting of the Basins of 
the Great Lakes. 
This report which is ready for press, lias been prepared by Prof. Wm. 
If. Hobbs. Tt will have special value to school and college libraries and 
teachers of physiography and geology. The text is beautifully illustrated 
with numerous pen drawings especially prepared for this report. 
Correspondence. 
The Survey receives by mail many requests for information on sub- 
jects of wide range. These receive the personal attention of the Di- 
rector and constitute no small draft on his time when not on duty in 
the field. Some idea of the number and character of the inquiries re- 
ceived may be gained by a glance at the tabulation below, which includes 
only such inquiries as have been answered by letters. Requests for 
publications, i. e., reports, maps, etc., are not included in this classifi- 
cation, nor the many requests delivered in person in the office. Some re- 
quests are for information on two or more subjects which explains the 
higher total under classification by subjects. Neither list includes a 
large number of inquiries which have been received by the Chief Field 
Naturalist in charge of the biological division. 
By calculation it has been ascertained that the number of requests 
for information thus far in this year exceed those of last: year by about 
30%. 
