12 FLORIDA GEOLOGICAL SURVEY-I3TH ANNUAL REPORT

est and desirable to have data on the fluctuation of flow which could be gotten only by records covering a stated period.
 Co-operation in the matter of the gauging of streams could be arranged with the Water Resources Branch of the United States Geological Survey and it is urged that provision be made for entering into such co-operation.

 CO-OPERATION WITH OTHER ORGANIZATIONS.

 The Florida Geological Survey has co-operated with the United States Geological Survey, as in former years, in the collection of statistics on the mineral production in Florida. This co-operation has been found highly desirable and advantageous since it eliminates the possibilities of discrepancies in statements which might occur when such statistics are collected separately by each Survey.

 TOPOGRAPHIC MAPPING.

 In this day of rapid development in the State coupled with undertakings of vast magnitude such as the enormous drainage projects, the plans for and the construction of permanent systems of highways, renewed activity in railroad extensions, etc., nothing could better serve as an essential aid in this development than detailed topographic maps. These maps are as accurate as the scale used (approximately a mile to the inch) will allow, showing every natural surface feature, such as rivers and creeks, springs, lakes, swamps and marshes, hills and valleys, sink-holes and rock outcrops in addition to artificial features as cities and towns, schools, .churches and other buildings, railroads, highways, as well as minor roads, and bridges. In fact, such maps as these prepared by the United States Geological Survey are indispensable to the most intelligent development of many of the State's resources and industries. With their aid the construction engineer can lay out a rightof-way for either highway or railroad without the expense of the preliminary survey and the drainage engineer can lay out a system of canals and ditches in the office almost to better advantage than in the field. To the general public, and particularly to those who travel, the maps are of great convenience and benefit, for a moment's glance reveals the exact physiography and general nature of the country mapped.