54 



SCIENCE. 



[Vol. XII. No. 287 



ceed in getting any definite information from it. Preliminary, there- 

 fore, to a description of these maps, and preliminary to an enumera- 

 tion of some of the practical uses which they have, the question as 

 to the authority for making them should be answered. 



It is the purpose of the Director of the United States Geological 

 Survey to make the geological map of the United States a practi- 

 cally useful one. It will not only show the character, extent, and 

 positions of the rocks that underlie the surface, in a general way, 

 but it will aim to show them exactly where they are in nature, and 

 their relation to the surface of the ground, so that a person in pos- 

 session of one of these maps may go and find the outcrop of any 

 particular stratum, if it has an outcrop, learning from the map 

 whether it is at the top or on the side of a hill, or in a valley, and 

 its relative position, not only to other strata, but to the prominent 

 landmarks of the adjacent country. But, in order to locate the 

 geological features of a section of country accurately, it is necessary 

 to have an accurate map showing the topographic features of the 

 section, and no such maps had been made until the United States 

 Geological Survey took up the work. 



The topographic maps now being made are to be the basis of 

 the geological work. Without them the latter would be in great 

 degree useless. The preparation of them is the necessary prelim- 

 inary work to the geological survey, and, as Major Powell's bureau 

 is authorized to make a geological map of the United State's, that 

 authority necessarily implies authority to do the necessary prelim- 

 inary work. 



But good topographic maps, even when made primarily to be 

 used as the basis of a geologic survey, have an incidental value in 

 many other ways, and it is entirely proper, it is very desirable, in- 

 deed, that they shall be utilized in every possible manner. Not a 

 single state, except two which will be referred to later, has to-day 

 even a fairly good map of its area. The best are inaccurate and 

 show little or nothing of the topography. The river courses, the 

 larger ponds and lakes, and the higher hills or mountains are ap- 

 proximately located upon most of them, but aside from these more 

 prominent features they give no idea of the character of the face of 

 the country. Where roads are laid down there is generally nothing 

 to show whether they extend over a rolling, hilly, or flat country ; 

 and any one who should attempt to drive across the country with 

 one of the best of these maps as a guide is pretty sure to get lost 

 and have to inquire the way. In many of the existing maps the 

 culture, that is the houses, with the names of their owners or oc- 

 cupants, and other transient features in which individuals are in- 

 terested, are given with considerable detail, but many permanent 

 natural features are omitted. The former make a map sell ; the 

 latter make it of practical use in a hundred different ways. 



Several of the States, recognizing the importance of having good 

 maps of their areas, have appropriated money for that purpose, and 

 commissions have been appointed to supervise the work of making 

 them. But, as it is the purpose of the United States Geological 

 Survey to make topographic maps of the entire country as bases for 

 its geological maps, and as it has the instruments, trained expert 

 topographers, and an organization perfected by which maps can be 

 made much cheaper and better than they can be made by any 

 special force organized for that purpose, it is an obvious economy 

 for the States to employ the Geological Survey to make these maps, 

 even though they have to pay the entire expense of them, rather 

 than to attempt to do it themselves. 



The general government also derives a direct benefit from this 

 co-operation. If the States do not make topographic maps of their 

 areas the United States Geological Survey will do so for its own 

 purposes. If the States do make the maps, but make them in their 

 own way, they will not be uniform with those made by the Geolog- 

 ical Survey or with each other, so that, while they may be very 

 good maps, they will be of much less use in making a geological 

 map than if the uniformity referred to was preserved. In fact, the 

 United States Geological Survey would eventually have to go over 

 the same ground and make its own maps. On the other hand, if 

 the money appropriated by the States for map making is paid over 

 to the Geological Survey and used as far as it will go in paying the 

 expenses of making the maps, the cost to the general government 

 of getting such topographic maps as it needs is reduced by the 

 amount of the State appropriations, and the expense to the States 



is lessened by the amount that the general government contrib- 

 utes. 



Three States have thus far availed themselves of the opportunity 

 to co-operate with the United States Geological Survey in making 

 topographic maps of their areas. — Massachusetts, New Jersey, and 

 Rhode Island. The maps of the first two have been completed 

 and are now in the hands of the engravers. For each State there 

 will be a large atlas of beautiful copper-plate sheets showing with 

 almost absolute accuracy the location of every natural feature of 

 the country, the altitude of every point, and, by contour lines, the 

 steepness of all hills, the positions of cities, towns, villages, and 

 post-offices, the courses of the roads, railroads, canals, etc., and, 

 in general, every thing that is permanent in its character as distin- 

 guished from that which is temporary, or of individual rather than 

 general interest. 



The topographers are now in the field at work upon the Rhode 

 Island map, and it will be completed this season. The area of the 

 Stale is about eleven hundred square miles, and of this about four 

 hundred square miles has already been mapped, leaving about 

 seven hundred square miles still to be done. 



Besides the work in these three States, the United States Geolog- 

 ical Survey has made topographic maps of the Appalachian belt 

 extending through parts of the States of Virginia, West Virginia, 

 North Carolina, South Carolina, Georgia, Alabama, Kentucky, and 

 Tennessee. Work has also been done in Missouri and Kansas, 

 and a large area in those two States has been mapped. A party 

 has been at work for two years around Fort Smith in Arkansas, 

 and about four thousand square miles have been mapped in Texas. 

 Around Madison, Wis., a small area has been surveyed for the 

 benefit of Professor Chamberlin's work on glacial geology, and an 

 experimental start has been made in Iowa. This work has all been 

 done by the United States Geological Survey without the co-ope- 

 ration of the States. Some work has also been done in the Rocky 

 Mountain region supplemental of that of the Powell, Hayden, King, 

 and Wheeler surveys, which was done before the United States 

 Geological Survey was organized, but which will be utilized. 



The topographic maps of the United States Geological Survey 

 are made upon three' different scales. Iji the first, or smallest 

 scale, one unit of distance on the map represents 250,000 units of 

 distance in nature, or four miles in nature is represented by one 

 inch on the map. The second scale is twice as large as the first, 

 or I to 125,000, — two miles to an inch, — and the third one-fourth 

 as large as the first, or i to 62,500, — one mile to an inch. In the 

 maps of the smallest scale an atlas sheet, when it is engraved, will 

 represent an area included within one degree of latitude and one 

 degree of longitude. If the second scale is used there are four atlas 

 sheets to a degree, and when the largest scale is employed it re- 

 quires sixteen atlas sheets to cover one degree of latitude and one 

 degree of longitude. The maps of Massachusetts, Rhode Island, 

 and New Jersey are made upon the largest scale. 



The question as to the best scale for maps and the minuteness 

 of detail that it is wise to attempt to represent has been a great 

 deal discussed by map-makers, but no agreement has been reached. 

 The publication scale of the United States Geological Survey maps 

 and the size of the sheets which the topographers use in the field 

 have necessarily no definite relation to each other. Some men do 

 better work upon a large than upon a small sheet, but the tendency 

 is, with every year's experience, to work nearer and nearer to the pub- 

 lication scale; that is, to put Into the original map all that can be 

 shown on the engraved sheet without confusion, and to omit other 

 details. 



The questions that are asked the topographers when they are in 

 the field disclose the particular features of a map In which the peo- 

 ple are most interested. For instance, in Rhode Island great in- 

 terest is manifested In the development of water power and also in 

 regard to the altitude of the higher hills of the State. In explana- 

 tion of the frequent question whether this hill or that Is not the 

 highest in the State, it may be said that a great many of the farm- 

 ers of Rhode Island are becoming more dependent upon summer 

 boarders than upon the products of their generally sterile lands for 

 their support, and every one whose house is on the top of a hill 

 would like to be able to say that it is on the highest point In the 

 State. How little was known about the relative altitudes of the 



