A second object exhibited was a pestle found by Mr. King, who was at one time General Director of the United States Geological Survey, and is an expert whose judgment on such matters should be final, and who had no doubt that the gravel in which he found the object must have lain in place ever since the lava came down and covered it. The third object was a mortar taken from the old gravel at the end of a tunnel driven diagonally 175 feet from the western edge of the basalt cliff, and 100 feet or more below the surface of the flat top of Table Mountain, as supported by evidence entirely satisfactory to Professor Wright, who had just visited the locality and cross-examined the principal witnesses. This may prepare us to consider the case of the celebrated Calaveras skull as by no means an isolated or exceptional one, but antecedently probable from the number of human implements found in the same gravels, under the same beds of basalt and lava, at Table Mountain and numerous other places. Professor Wright in the article already referred to, which is the latest on the subject, and made after his visit to California in 1890, which he says enabled him to add some important evidence, sums up the facts as follows-- "In February 1866, Mr. Mattenson, a blacksmith living near Table Mountain, in the county Calaveras, employed his spare earnings in driving a tunnel under the portion of the Sierra lava flow known as Bald Hill. At a depth of 150 feet below the surface, of which 100 feet consisted of solid lava, and the last fifty of interstratified beds of lava, gravel, and volcanic tuffs, he came upon petrified wood, and an object which he at first took for the root of a tree, thickly encased in cemented gravel. But seeing what he took for one of the roots was a lower jaw, he took the mass to the surface, and gave it to Mr. Scribner, the agent of an express company, and still living in the neighbourhood, and highly respected. Mr. Scribner, on perceiving what it was, sent it to Dr. Jones, a medical gentleman of the highest reputation, now living at San Francisco, who gave it to Professor Whitney, who visited the spot, and after a careful inquiry was fully satisfied with the evidence. Soon afterwards Professor Whitney took the skull home with him to Cambridge, where, in conjunction with Dr. Wynam, he subjected it to a very careful investigation to see if the relic itself confirmed the story told by the discoverer, and this it did to such a degree that, to use Professor Wright's words, the circumstantial evidence alone places its genuineness beyond all reasonable question."