_The topography and later shore-line are taken from the Survey of Mr. Clarence King, U.S. Geologist; the earlier shore-line from the Survey of Capt. Howard Stansbury, U.S.A._] The “abnormal change” of the lake may then be described as an infilling or rise of the water whereby its ordinary level has been raised 7 or 8 feet and its ordinary area has been increased a sixth part; and this appears to be distinct from the limited oscillation and annual tide, which may be regarded as comparatively normal. To account for it a number of theories have been proposed, and three of them seem worthy of consideration. They appeal respectively to volcanic, climatic, and human agencies. VOLCANIC THEORY. It has been surmised that upheavals of the land, such as sometimes accompany earthquakes, might have changed the form of the lake bed and displaced from some region the water that has overflowed others. This hypothesis acquires a certain plausibility from the fact that the series of uplifts and downthrows by which the mountains of the region were formed have been traced down to a very recent date, but it is negatived by such an array of facts that it cannot be regarded as tenable. In the first place, the water has risen against _all_ the shores and about every island of which we have account. The farmers of the eastern and southern margins have lost pastures and meadows by submergence. At the north, Bear River Bay has advanced several miles upon the land. At the west, a boat has recently sailed a number of miles across tracts that were traversed by Captain Stansbury’s land parties. That officer has described and mapped Strong’s Knob and Stansbury Island as peninsulas, but they have since become islands. Antelope Island is no longer accessible by ford, and Egg Island, the nesting ground of the gulls and pelicans, has become a reef. Springs that supplied Captain Stansbury with fresh water near Promontory Point are now submerged and inaccessible; and other springs have been covered on the shores of Antelope, Stansbury, and Fremont islands. In the second place, the rise of the lake is correlated in time with the increase of the inflowing streams, which has been everywhere observed by irrigators, and it is logical to refer the two phenomena to the same cause. And, finally, if upheaval could account for the enlargement of the lake, it would still be inadequate to account for the maintenance of its increased size, in the face of an evaporation that yearly removes a layer several feet in depth. The same compensatory principle that restricts the “limited oscillation” would quickly restore the equilibrium between inflow and evaporation, in whatever manner it was disturbed. CLIMATIC THEORY.