By JOSEPH SILAS l)ILLER. Twenty years ago Crater Lake was unknown to the general public, but since then a knowledge of its remarkable features has been spread abroad through the press, and Congress recognized its worth as an educational feature and made it a national park by the act approved May 22, 1902. As defined in the bill, the park is "bounded north by the parallel forty-thi-ee degrees four minutes north latitude, south by forty-two degrees forty-eight minutes north latitude, east by the meridian one hundred and twenty-two degrees west longitude, and west by the meridian one hundred and twenty-two degrees sixteen minutes west longitude, having an area of two hundred and forty-nine square miles." The Ashland sheet of United States Geological Survey, on the scale of 4 miles to 1 inch, includes the area lying between meridians 122 and 123v and parallels 420 and 430. This map includes the region between Ashland and Crater Lake. On account of the great scientific interest of Crater Lake a special map, known as the Crater Lake special sheet, was prepared on the scale of I mile to an inch, including the country immediately adjacent to Crater Lake, between meridians 1220 and 1220 15' and parallels 42 50' and 430 4'. From these two maps the accompanying map of the Crater Lake National Park (Pl. I) has been prepared. The two papers published here refer practically to the whole region included in the National Park. The one. Part I, treats primarily of the geology, the development of the great volcano, Mount Mazama, and its collapse, which gave birth to Crater Lake; the other, Part II, deals with the petrography, and gives a special description of the various rocks occurring in the park. Oriqin qf the name Jfo ant Jhozamaca.-A great impetus to the spread of information concerning Crater Lake was given by the Mazamas of Portland, Oreg., who held a meeting at the lake in August, 1896, which attracted many visitors. The prina An account of the discovery of Crater Lake and reference to its literature will be found in