454 KANSAS CITY REVIEW OF SCIENCE. 



It is well to state at the outset that the pay-dirt is manifestly all of one forma- 

 tion and of one geological age, wherever we find it. Some of it is lying opened 

 and exposed; we will let that pass. Some of it is covered by volcanic rock, and 

 of course is itself older than the rock \ that is, the lava flowed out and covered 

 the gravel after the gravel was in its present form and position. That is sure, 

 for after the gravel was thus imbedded, it has most certainly never been disturbed 

 until within these last few years the miners have dug into it in search of gold. 

 To the gravel then below the lava, we will turn our attention. 



Looking out from Carson Hill, in Calaveras County, you see across the 

 Stanislas in Tuolumne, a long mountain ridge. It extends down into the plain, 

 where it ends very abruptly, while its upper limit is out of sight away among the 

 main heights of the Sierra Nevada. It looks like a huge railroad embankment,, 

 and suggests to you that idea, but men do not make railroad dykes forty miles 

 long and 1500 to 3000 feet high. That which gives it its smooth even upper sur- 

 face is basalt, that is, ancient lava; the lower part is of looser materials. The 

 thickness of the basalt varies at different points, being here and there hundreds 

 of feet thicker than it is at other places a mile or two either above or below. 

 This is Table Mountain, a name which has been famous in the history of Cali- 

 fornia, as we shall see. 



The question occurs to us : How came Table Mountain to exist ? That basaltj. 

 when it was erupted, was fluid like other lava. How could it be piled up so< 

 thick and so abrupt (for its sides are often perpendicular) on that high mountain 

 ridge, and remain there? Why did it not spread itself out laterally and cover 

 the plain ? But one answer to these questions can be given : There was nO' 



plain. 



When that eruption took place and the crater or fissure opened, far up near 

 the summit of the Sierra Nevada, it naturally flowed into the bed of the first 

 stream which crossed its track. This it filled and followed down until, when 

 the eruption ended, the old river bed, away down to the plain, was blocked up 

 by the solid volcanic rock, and the waters which should have been there, were 

 finding their way by some other track. 



As time passed on, the side of the mountain range was yielding to at- 

 mospheric influences. The flowing water was carrying off" the softer material on 

 each side of the hard basalt, which had filled and obliterated the old river-bed ; 

 the Tuolumne River on the south and the Stanislas on the north, with their tribu- 

 taries, were formed, and scooped out their present valleys, and thus Table Moun- 

 tain, which had been deposited in the bed of an old mountain torrent, with high 

 ridges confining it, became itself a ridge, standing like a wall above all which ad- 

 joined it. But beneath the basalt lay the stones and gravel and sand and clay 

 which made the bed of the ancient torrent, as they do of the modern streams. 

 And like the modern streams, their predecessor in age, but not in locality, was 

 rich in gold, and thanks to this gold, we know something of the Ancient Man'^of 

 Calaveras and Tuolumne. We know him because he has left his mark among 

 the stones and gravel. 



