CALIFORNIA RANGES ADJACENT TO SOUTHERN NEVADA 239 



is a closely coaipressed syncline overthrown toward the east. Mr Wal- 

 cott's section shows, in general, synclinal ridges and anticlinal valleys, 

 and both in his section and in Mr Gilbert's the faults have no expres- 

 sion in the topography. 



Mr Walcott has pointed out that the structure of this range is of the 

 Appalachian type, and from the facts given we must conclude that the 

 relief is due to long continued erosion. 



Gra'pevine and Funeral ranges. — The Funeral mountains are the southern 

 continuation of the Grapevine range, but are not so high. There is no 

 interval between the two, but a steep mountain scarp on the south side 

 of Pyramid peak serves as a boundary. To the north of this line the 

 Grapevine range is made up of Paleozoic strata, and to the south the 

 Funeral mountains consist of Tertiary sediments and volcanics. 



At Boundary canyon the Grapevine range consists essentially of an 

 anticline* cut by longitudinal and transverse faults, while at Furnace 

 creek, which is near the above-defined line between the mountain groups, 

 the writer observed two anticlinal folds with an intervening syncline. 

 Near the latter place the topography seems to have been, to a large ex- 

 tent, directly determined by the folding, so closely does one correspond 

 to the other. This correspondence is more striking in the Funeral range 

 proper. Here Furnace Creek valley follows along the bottom of a curv- 

 ing syncline, and on both sides are anticlinal ridges whose slope is the 

 same as the dip of the constituent beds. Of these ridges, that on the 

 west, sometimes called Black mountains, is most important. The rocks 

 of this dip down into Death valley, which appears to be a synclinal 

 trough. In these folds has been involved not only the whole Tertiary 

 section, but also the overlying olivine-basalt, which, by correlation with 

 other occurrences, may be tentatively classed as early Pleistocenef ; the 

 movement must therefore have been prolonged into very recent times. 

 The structure recalls the diagram of the Jura mountains given by Davis. J 



But previous to this recent folding, as the writer has ascertained, there 

 existed prominent mountains, representing the present Grapevine range, 

 whose rocks were little folded and whose relief must have been due to 

 pre-Tertiary erosion ; and to these earlier mountains the Grapevine range 

 owes much of its relief and its elevation above the Funeral range. Thus, 

 while the Funeral mountains may be said to be due entirely to deforma- 

 tion, since folds and probably faults are directly expressed at the sur- 

 face, the Grapevine range owes its origin to simple erosion plus simple 

 deformation. 



*G. W. Gilbert: Wheeler Surveys West of the Hundredth Meridian, vol. iii, p. 33. 

 t J. E. Spurr: Jour. Geol., vol. viii, no. 7, p. 63G. 

 X Physical Geography, Boston, 1899, p. 168. 



