THE FORM OF LIGHTXIA^G-RODS. 



399 



the mesas and plateaus farther away trom tlie mountains, but not 

 lower than the flood-plain of the river. 



I have endeavored above to explain the relation of the valleys of 

 tlie Uinta Mountains to the stratigraphy, or structural geology, of the 

 region, and, further, to state the conclusion reached, that the drainage 

 was established antecedent to the corrugation or displacement of the 

 beds by faulting and folding. I propose to call such valleys, including 

 the orders and varieties before mentioned, antecedent valleys. 



In other parts of the mountain-region of the West, valleys are found 

 having directions dependent on corrugation. I proj^ose to call these 

 consequent valleys. Such valleys have been observed only in limited 

 areas, and have not been thoroughly studied, and I omit further dis- 

 cussion of them. 



In many cases, there can be no doubt that the present courses of 

 the streams were determined by conditions not found in the rocks 

 through which the channels are now carved, but that the beds in 

 which the streams had their origin, when the district last appeared 

 above the level of the sea, have been swept away. I propose to call 

 such superimposed valleys. Thus the valleys under consideration, if 

 classified on the basis of their relation to the rocks in which they 

 originated, would be called consequent valleys ; but, if classified on the 

 basis of their relation to the rocks in which they are now found, would 

 be called supei'imptosed valleys. 



-- 



THE FOEM OF LIGHTNIXG-KODS. 



By Peof. JOHN PHIN. 



THE season when the attention of the public will be directed to 

 protection from lightning is now approaching, and it is of the 

 utmost importance that correct views in regard to the construction 

 and erection of lightning-rods should prevail. We have in this coun- 

 try a class of men who have devoted themselves to the business of 

 making money out of the fears which thunder and lightning inspire, 

 and it unfortunately happens that the majority of these men care more 

 for the money which they obtain than for the actual protection which 

 they afford to their customers. To them, complicated arrangements, 

 that can be defended with any show of reason, are a most important 

 matter, for, on the ground of greater cost and efficiency, a more lib- 

 eral harvest is obtained. In this connection there has been no more 

 fertile source of imposition than the fallacy that lightning travels only 

 on the surface of metallic conductors, for it has led to the construction 

 of lightning-rods of which the cross-sections are stars, tubes, and all 

 sorts of complicated devices. A recent note in The Populae Sci- 



