Mineralogy and Geology. 287 



Baltimore six hundred tons at this time, and they estimate the amount of 

 copper that they will ship at from nine hundred to one thousand tons 

 before the close of navigation in November next. This mine has been 

 wrought with proper energy, and will richly repay the owners. There 

 are several other native copper mines here that are equally promising, 

 and will produce well when wrought with proper energy and skill. 



Copper Falls mine is an example, and is doing well. The North- 

 west is another full of promise, and I have seen others which look 

 very rich, but which are not yet opened deep enough to exhibit their 

 contents. The shafts at the Cliff mine are 205 feet deep, and the hill 

 above shows the vein in the face 213 feet higher, so that we know that 

 the copper extends at least 418 feet. Those who were surprised that I 

 recommended working mines for native copper, should come and see 

 and they would believe. The case is indeed a new one, and we watch 

 with interest the results. 



Native silver is found mostly at and near the junction of the trap 

 and sandstone where the veins end, not passing into the sandstone. 



6. Observations on the " Old Crater^ adjoining Kilauea, {Hawaii,) 

 on the east ; by Rev. C. S. Lyman, (from a letter dated Upper Califor- 

 nia, January 30, 1848.) — The " Old Crater" is a pit a mile in diameter, 

 and five hundred or six hundred feet deep, separated from the present 

 active crater by an isthmus of earth, about a quarter of a mile in width. 

 I spent a day ransacking it. The bottom is covered with lava in thick 

 strata resembling ice left in the bottom of a pond after the water has been 

 drawn out. This covers an area three-quarters of a mile in diameter, 

 and rises around the sides of the bowl-like concavity some forty or fifty 

 feet above the level of the bottom. I noticed projecting perpendicu- 

 larly from the bottom, a great number of stone pillars of various sizes, 

 from one to two feet, and of heights from one to twenty feet. On 

 breaking off some of them I found them tubular and filled with char- 

 coal. The specimen in the box is a portion of one of these tubes with 

 the lava injected into the seams of the charcoal. I could conveniently 

 bring away only this specimen, hoping to get more at another visit 

 which has not yet occurred. The philosophy of this specimen I take 

 to be this. At some comparatively recent period, the lava burst out far 

 U P the sides of this pit and even upon the neck of land between the 

 two craters and flowed down into the bottom — at that time a forest — 

 filling it up to the depths of forty or fifty feet, with a lake of lava.* 

 The lava in contact with the trees, would be cooled at once into an en- 

 casement of stone from two to six inches in thickness, while the rest of 

 the mass remained fluid. The trees would of course be almost instantly 

 reduced to charcoal, and a crust often a foot or so in thickness must 

 have cooled on the surface of the lake. The lake must then have been 

 drained oft'subterraneously, while the crust descending, like the ice on 

 a pond when drawn off, would be pierced by these solid encasements 

 pf the trees, and finally lie scattered over the bottom in huge cakes, as 

 ice would among stumps on the bottom of the pond, leaving these cu- 

 rious tree-encasements projecting as they now do. 



In 1832. See Geol. Rep. Expl. Expedition by J. D. Dana, pp. 186, 211 



