This is not a solitary instance, for the Professor reports as the result of his personal inquiries only a year ago in the district, that "the evidence that human implements and fragments of the human skeleton have been found in the stratum of gravel underneath the lava of Table Mountain seems to be abundantly sufficient;" among others a fragment of a skull which came up with a bucketful of dirt from 180 feet below the surface of Table Mountain at Tuolumne. Dr. Wallace, in an article on the "Antiquity of Man in North America," in the _Nineteenth Century_ of November 1887, thus enumerates some of the principal instances-- "In Tuolumne county from 1862 to 1865 stone mortars and platters were found in the auriferous gravel along with bones and teeth of mastodon 90 feet below the surface, and a stone muller was obtained in a tunnel driven under Table Mountain. In 1870 a stone mortar was found at a depth of 60 feet in gravel under clay and 'cement,' as the hard clay with vegetable remains (the old volcanic ash) is called by the miners. In Calaveras county from 1860 to 1869 many mortars and other stone implements were found in the gravels under lava beds, and in other auriferous gravels and clays at a depth of 150 feet. In Amador county stone mortars have been found in similar gravel at a depth of 40 feet. In Placer county stone platters and dishes have been found in auriferous gravels from 10 to 20 feet below the surface. In Nevada county stone mortars and ground discs have been found from 15 to 30 feet deep in the gravel. In Butte county similar mortars and pestles have been found in the lower gravel beneath lava beds and auriferous gravel; and many other similar finds have been recorded.... "Even these Californian remains do not exhaust the proofs of man's great antiquity in America, since we have the record of another discovery which indicates that he may, possibly, have existed at an even more remote epoch. Mr. E. L. Berthoud has described the finding of stone implements of a rude type in the Tertiary gravels of the Crow Creek, Colorado. Some shells were obtained from the same gravels, which were determined by Mr. T. A. Conrad to be species which are 'certainly not older than Older Pliocene, or possibly Miocene.'" I do not dwell on the discoveries which have been made of human implements and skeletons in the cases of Minas Geraes in Brazil, and in the drift or loess of the pampas of Buenos Ayres, for although associated with extinct animals usually considered as Pliocene, there is a difference of opinion among competent geologists, whether the deposits are really Tertiary or only early Quaternary.