352 



SCIENCE 



[Vol. XVIII. No. 464 



materials, how and to what extent does a geological survey ac- 

 complish this? Well, to answer this question satisfactorily we 

 must first determine what is meant by the term "discovery." 

 The date when the existence of any one material first became a 

 fact in the consciousness of man can never be stated. It is prob- 

 able that the gold in California was known to exist by the abo- 

 rigines, merely as glittering particles or nuggets of undetermined 

 properties, long before the " white man'" made the f'Bct of its ex- 

 istence known, or, as we say, discovered it. It is probable that 

 many a block of silver ore was seen and handled unrecognized by 

 the pioneer long before mining first began. Again, it is probable 

 that the primeval savage of California both knew of the existence 

 of the gold and was familiar with its general properties and value, 

 yet from the isolation and barbarism of his surroundings the fact 

 of existence was never made through him the property of the 

 civilized world. Hence, so far as its effect on civilization is con- 

 cerned, we must define discovery of existence as that event 

 whereby a material is brought to the knowledge of an individual 

 who recognizes it and who has a conception of its value, and who 

 transmits the fact of existence to the world. Such a work of 

 discovery constituted a large part of the functions of the early 

 explorations throughout the country of the earlier geological sur- 

 veys. The more general facts of existence were then sought af- 

 ter, knowledge was so imperfect. This was the necessary foun- 

 dation for further investigation for future development. Nowa- 

 days the work of geological surveys is tending more to the solution 

 of other questions. 



With reference to Missouri as a whole, it may safely be said 

 that we do not look for the discovery in the future of the existence 

 in considerable quantity of a single mineral substance of great 

 economic value, the existence of which is not already known. 

 But though, in this large sense, such is, strictly speaking, true, in 

 a narrower sense, and in the sense that the existence of materials 

 in special localities is being brought to the knowledge of men who 

 will recognize them and make the facts known to the world, dis- 

 covery is still in progress in the State and constitutes an important 

 part of the work of the geological survey. Discoveries of this 

 kind of iron-ores, zinc and lead-ores, clays and coals, and other 

 materials have been made throughout the State during the past 

 year, and the result^ will be published in the forthcoming reports. 

 Such discoveries are made by all well-conducted geological sur- 

 veys, and they are thus extensive contributois to the first require- 

 ment for the development of a mining industry. 



The discovery or determination of the quantities and distribu- 

 tion of materials is, however, nowadays recognized as one of the 

 principal directly economic functions of a geological survey, and 

 it is the work requiring the highest attainments and the most stu- 

 dious and exhaustive investigation. The science of geology is 

 here called into play, and the knowledge accumulated during 

 many years by multitudes of observers is applied for the solution 

 of the problems The mere existence of a material may be deter- 

 mined by any one with a small stock of knowledge and a ram- 

 bling search. The quantity and distribution can generally be de- 

 duced only from a host of facts gathered with close and patient 

 observation, and then studiously and logically handled. It is first 

 an inductive and then a deductive process. The general laws and 

 facts of geology have to be known before a correct diagnosis can 

 be made. Therefore, just as a physician can best treat a patient 

 if he knows his structure, constitution, and habits well, so a 

 geologist can best accomplish his results if he knows thoroughly 

 the geological structure of the area he is examining, and the laws 

 governing its phenomena. Hence it has come to be recognized in 

 theory, and is accepted in the best practice, that the most valuable 

 and far-reaching results are attained when the fundamental facts 

 of the geology of an area are mastered. A due regard for logic 

 demands that the general principles shall be established before we 

 attempt the solution of particular cases. To illustrate, most of 

 the rocks exposed in Missouri and adjacent States are what are 

 called clastic or sedimentary rocks, and occur in strata, or layers, 

 piled upon each ether like the leaves of a book. Each layer is, 

 however, not co-extensive with the area of the State, but gener- 

 ally the uppermost occupies the smallest area, and those underly- 

 ing it protrude beyond it successively in constantly expanding 



zones, so that their limits are defined on the map by a series of 

 roughly concentric lines, or, as has been said by Lesley, like the 

 grain lines of a polished piece of wood, planed at a low angle 

 across the grain. 



Some minerals of value frequently characterize certain strata or 

 formations; this is especially the case with coal, iron, and clays, 

 and sometimes with lead and other ores. Hence, if the distribu- 

 tion of these strata is once defined, through the study of the geol- 

 ogy, the value of the knowledge as a guide to prospecting for all 

 future will be readily appreciated. This definition of the areas of 

 the strata or geological formations is hence recognized as an im- 

 portant duty of a geological survey. Here it is that fossils are of 

 use. Some fossils are restricted to certain strata, oi-, more exactly 

 speaking, different strata have different faunal characteristics; 

 hence, fossils become ear marks which help us to recognize out- 

 crops as belonging to certain formations and lead us to a correct 

 classification of the scattered occurrences. For example, suppose 

 that over a coal bed worked at a point, A, is a bed of limestone 

 characterized by certain fossils At a point, B, is another coal 

 mine, and the question arises as to whether the bed at B is the 

 same as that at A. Or, in other words, have we at B one or two 

 coal beds, a question of much economic importance. A close ex- 

 amination in the creek bed below the outcrop of coal at B reveals 

 the existence of a limestone bed with the same fossils as those 

 found over the coal bed at A. Hence, the inference is direct that 

 that the coal of A underlies the coal of B, and will be found on 

 investigation. 



In working out the distribution of the geological formations on 

 the ground this end is the immediate and controlling one to the 

 field geologist, and its economic value is not always in his mind ; 

 and to a still smaller degree is the fact ordinarily appreciated by 

 the layman ; hence the former's operations are frequently re- 

 garded, by those of ultra utilitarian minds, as mildly idiotic. In 

 illustration, an assistant of mine on the Arkansas survey, a capa- 

 ble and well-trained man, was at one time engaged in tracing the 

 outcrops or limits of a certain stratum of sandstone in the coal 

 measures of that State. He stopped one night at a farmer's house 

 for lodging. After the evening meal, the host and his guest hav- 

 ing settled themselves in front of the blazing log heap of a fire, 

 which all Arkansas travellers enjoy, the farmer, learning the vo- 

 cation of his guest, thought he would seize the opportunity to 

 obtain some useful information. "Well, my friend," he began, 

 "have you discovered any mineral about here?" "No," an- 

 swered the young man, who was somewhat shy aud non-com mu- 

 nicative. " Not found any !" echoed the farmer ; " well, now, 

 that's too bad. Don't you think you will find some soon?" he 

 questioned. "No," again answered the young man, who' was 

 strong in monosyllables. " Haven't found any and don't expect 

 to find any, I " ejaculated the somewhat astonished questioner; 

 "well, what do you stay here for, then?" '-I am not looking 

 for mineral," was the young man's brief reply. " Not looking for 

 mineral ! "exclaimed the dumbfounded and now somewhat irate 

 farmer; "then what in the name of creation is your work good 

 for?" Here, then, were two men at loggerheads simply for lack 

 of a little explanation. The young man was tracing a stratum, 

 which, when transferred to the map, would define the area of an 

 important coal bed. Absorbed in the immediate object of his 

 work, he lost sight of a part of its outcome; he was in one sense 

 engaged in the actual " discovery of mmeral " without being en- 

 tirely conscious of it. A few words of explanation might have 

 made all clear. 



These illustrations will suffice to explain hotv the determination 

 of the general facts of stratigraphic structure are of broad eco- 

 nomic value. The definitions of the members of the oil-sand 

 group, in Pennsylvania, of the Trenton limestone in Ohio, per- 

 mitted the intelligent and rapid development of the oil industry. 



Similarly the determination of the sources of our ore bodies, of 

 their modes of formation is of fundamental importance, is indis- 

 pensable for the constniction of the correct theory of their distri- 

 bution, which alone will lead to their full development, and which 

 will prevent waste through expenditure in the wrong direction. 

 I could illustrate this in detail, but time will not permit, and I 

 think the principle is akeady made clear. Such are some of the 



