THE LODE QUESTION. 117 



been no doubt the channels of ore-bearing solutions. These masses in 

 ordinary veins might have been surrounded by vein matter, but, owing to 

 the peculiar manner in which ore was deposited in this locality, the sur- 

 rounding fissures do not often show ore. These masses of rock then take 

 the place of horses from a structural point of view, but do not answer the 

 current definition of the term, and a misunderstanding or an error is involved 

 either in calling them horses or in denying their structural analogy to horses. 

 If it were once admitted, however, that a mass of rock not substantially 

 inclosed in ore or secreted gangue minerals may be called a horse whenever 

 the fissures by which it is divided from the solid country belong to an ore- 

 bearing system the consequences would be serious, for a horse is always 

 regarded as a part of the fissure filling, as a portion of the vein or lode, and 

 the lode woidd then necessarily be coextensive with the fissure system. In 

 that case the term lode would be synonymous with mining region. The 

 quicksilver belt of California would be a single lode, as, too, the California 

 gold belt, and the great Arizona and Utah mineral zones would each repre- 

 sent a single complex vein. 



Classification of ore deposits according to different authors. Such an extended significa- 

 tion of the words lode and horse would also be wholly at variance with any 

 system of the classification of ore deposits which has hitherto been adopted, 

 for these depend to a very great extent upon the extei'nal form of ore bodies. 

 Von Cotta says:" "I divide all ore deposits primarily according to their 

 form into regular and irregular. The former fall into two groups, beds and 

 veins; the latter into stocks and impregnations." In the next paragraph he 

 savs: "A single aggregation of ore may consist of several separate deposits 

 of different forms." These passages make it as clear as possible that von 

 Cotta regarded a substantially regular tabular form as essential to a vein, 

 and when ore masses of different shapes are so associated as to imply a 

 simultaneous and common origin he would relegate them to different classes 

 without regard to the community of origin. Since von Cotta, two eminent 

 mining geologists, Grimm and von Groddeck, have written important, mono- 

 graphs dealing with the classification of ore deposits. Each has endeavored 

 to give greater weight to genesis in classification than von Cotta did. The 

 following table explains the classification of each of these authors: 



•Erzlagerstiitten, I., p. 2. 



