MEMORIAL OP CHARLES A. DAVIS 25 



The following letters pertain to his life in Ann Arbor in connection 

 with the Survey. First a letter or two regarding the beginning of the 

 Cooperative Topographic Survey: 



"303 South Division Street, 

 "Ann Arbor, Michigan, February 2, 1903. 

 "I think Mr. Hayes fails to realize, quite, the close connection between ecol- 

 ogy and geology— at least the historical side of geology. It seems to me that 

 it is here that biology and geology meet, and if ever we are to get at safe 

 approximations as to the length of time taken to develop certain given rock 

 systems, we must study by biological and 'ecological' methods combined with 

 geological studies on the conditions which we find existing in favorable places 

 at the present time. In other words, ecology is one of the meeting grounds of 

 biology and geology, as we ordinarily understand the term, and money spent 

 in ecological work of the right sort might properly come from a geological 

 source, as it would eventually, at any rate, help to solve strictly geological 

 problems." 



"303 South Division Street, 

 "Ann Arbor, Michigan, March 20, 1903. 



"Having just received the topographic map of the region about Ann Arbor 

 which has been made for the Michigan Geological Survey by the United States 

 Survey, I write to congratulate you on having made such a good start on such 

 an important work. From the standpoint of an educator, I can say that I 

 believe nothing has ever been done in the State which will be of such value in 

 teaching" geography, certain phases of geology, and physiography as this ; for 

 it will give teachers an absolutely correct and reliable map, not only showing 

 the streams and lakes of the region, but all the relief forms as well; hills, 

 valleys, plains, and old beach lines are all shown in a surprising way and one 

 which should be easily understood by the children. As a worker in the field 

 in various departments of natural history, but especially in forestry, I find It 

 hard to express the feeling of thankfulness which I have that I can have this 

 map to aid me in working out local conditions. It greatly simplifies the map- 

 ping of the distribution of different types of forest trees, hence of forests, and 

 will enable me to accomplish much more in a given time than if only the old 

 inaccurate privately published maps were available. Certain kinds of surface 

 configuration are accompanied by certain types of soil, and on this we know 

 there will be found certain kinds of forests ; so by simply inspecting this map 

 one may definitely prophesy what kinds of forests may be found in given dis- 

 tricts covered by the map. In botany, zoology, and geology these facts obtain 

 also, so that investigators in these lines are equally benefited. Real-estate 

 men here are very much interested in the map and say it means the saving of 

 an immense amount of time to them, for they have the country spread out 

 before them in their office and need not visit it to decide on the character of 

 the land. 



"Personally I believe also that for all engineering enterprises the map will 

 be very helpful. I know in investigating sources of water supply about Ann 

 Arbor I have found advance sheets of the map, with its accurate level lines, 

 a. great help in my study, since it enabled me to show the feasibility of several 



