F L. Ransome — Lava Flows of California. 359 



buttes, or clusters of peaks, such as the Dardanelles, composed 

 of remnants of the former volcanic cover. 



The Table Mountain Flow. — The first and longest of the 

 latite flows has been so designated from the fact that 

 it forms the conspicuous topographic feature west of Sonora 

 known as Table Mountain. Starting from Knight's Ferry, this 

 flow can be followed up the Stanislaus River for a distance of 

 about 8 miles to a point near Byrnes Ferry. Along this 

 distance the latite forms broad, flat tables, with black 

 rugged surfaces. The river has cut through the lava, and 

 flows in a picturesque gorge cut deep into the slaty rocks of 

 the Bed-rock series. At the brink of the gorge the edges of 

 the Table Mountain flow form vertical cliffs, usually showing 

 columnar structure. Near Byrnes Ferry the line of the old 

 channel turns eastward for about 4 miles, then again resuming 

 its northeast trend to form the long and imposing rampart of 

 Table Mountain. Owing to the general degradation of the 

 country immediately surrounding it, this portion of the flow, 

 with its strikingly even crest-line and bounding columnar cliffs, 

 is a very prominent feature in the landscape, and has been 

 quite fully described by Trask,* Whitney, f and others, all of 

 whom refer to it as a basaltic flow. Many tunnels have been 

 run beneath the lava of Table Mountain for the purpose of 

 exploiting the auriferous stream-gravels which were buried by 

 its eruption, and subsequently protected by its resistant mass. 

 Near Parrott Ferry the course of the lava-flow again swings 

 northwestward and crosses the present Stanislaus River, here 

 flowing in a deep gorge, 1000 feet below the dissected rem- 

 nants of the latite that rest upon the brows of the pre- 

 cipitous canon walls. From Parrott Ferry the formerly 

 continuous lava-stream is now traceable as a series of dissevered 

 patches, lying along the right bank of the main Stanislaus 

 River, and of its North Fork, to a point southeast of Big Trees. 

 Along this portion of its course the Table Mountain flow rests 

 indifferently upon a great variety of rocks, including slates, 

 schists, limestones, quartzites, and gneisses of the Bed-rock 

 series, and gravels, rhyolitic tuff, and andesitic breccia of the 

 Neocene member of the Superjacent series. As a general rule 

 the fragments of the flow hang upon the steep slopes of the 

 canon rim, forming flat benches which break off abruptly on 

 the river side in columnar cliffs. 



Southeast of Big Trees the line of flow crosses the North 

 Fork and can thence be followed as a line of dissevered frag- 



* Report on the Geology of Northern and Southern California. Sacramento, 

 1856, State Senate Doc. 14, p. 20. 



fGeol. Survey of California, vol. i, Geology, pp. 243-246. Also Auriferous 

 Gravels of the Sierra Nevada, Mem. Mus. Comp. Zool. Harvard Coll., vol. vi, 

 1880, pp. 131-137. 



