128 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. [TolY. 



grained sandstones. Higher up conglomerates occnr, and still higher 

 coarse conglomerates and breccias prevail. Interbedded with the mas- 

 sive, irregular beds of the latter rocks are always thin layers of sand- 

 stones and shales. The sandstones are fine-gTained, thinly bedded and 

 contain more or less tufaceous material. Their prevailing color is green- 

 ish and greenish-gray. They are apparently composed chiefly of materials 

 derived directly or indirectly from volcanic sources. In' no case are 

 pebbles of quartz or other granitic constituents found in either the sand- 

 stones or conglomerates. 



The exposures of strata in the first three or four hundred feet at the 

 base are not good, and but few of the silicified trunks appear above the 

 covering of vegetation. At the height of 500 feet, the occurrences be- 

 come very numerous, and the great size and fine state of preservation 

 of many of the trunks was a matter of much surprise. Prostrate trunks, 

 50 and 60 feet in length, are of frequent occurrence, and not a few of 

 these are as much as 5 or 6 feet in diameter. 



The standing trunks are generally rather short, the degradation of the 

 compact enclosing strata being so slow that the brittle trunks break 

 down almost as fast as they are exposed. In many cases the roots are 

 exposed, and may be seen penetrating the now solid rock with all the 

 original ramifications One upright trunk, of gigantic proportions, rises 

 from the enclosing strata to the height of twelve feet. By careful meas- 

 urement it was found to be ten feet in diameter, and as there is nothing 

 to indicate to what part of the tree the exposed section belongs, the 

 roots may be far below the surface, and we are free to imagine that 

 there is buried here a worthy predecessor of the giant Sequoias of Cali- 

 fornia. Although the trunk is hollow, and partly broken down on one 

 side, the woody structure is perfectly preserved, the grain is straight, 

 and the circles of growth distinctly markeG\ The bark, which still re- 

 mains on the firmer parts, is four inches thick, and retains perfectly the 

 original deeply lined outer surface. Specimens of the wood and bark 

 were collected, but no microscopic examinations have been made. It is 

 clear, however, that the tree was not a conifer. The strata which en- 

 close this trunk are chiefly dne-grained greenish sandstones, indurated 

 clays, and moderately coarse conglomerates. They have been built 

 around it as it stood in comparatively shallow, but doubtless quiet waters. 

 As would naturally be expected, these strata contain many vegetable 

 remains: branches, rootlets, fruits, and leaves are extensively enclosed. 

 One stratum of sandstone that occupies a horizon nearly on a level with 

 the present top of the giant tree contains a great variety of the most 

 perfectly preserved leaves. Such specimens as we were able to bring 

 away with us have been submitted to Professor Leo Lesquereux for 

 identification. They are found by him to belong to the Lower Pliocene 

 or Upper Miocene, and correspond in a number of their species with the 

 Chalk Bluffs specimens of Professor Whitney. They include— 



Aralia Whitneyi, 

 Magnolia lanceolatUj 



