Eeviews — American Journals, 285 



crevasses, filled in some cases with mud and water, in others, higher 

 up, with hard snow. The surface of the glacier was found to be 

 broken up into irregular stair-like blocks with smooth sides, and so 

 large that it was impossible for Mr. Blake's party to ascend them 

 without ladders or tools to cut footholds with. His sketches of the 

 bluffs of the great glacier are very striking, and his paper will form 

 a valuable contribution to the history of glacial phenomena. 



In the same number, Mr. C. A. White gives a sketch of the 

 Geology of South-Western Iowa, with a clear and concise summary 

 at the end of the nature and succession of the rocks from the Lower 

 Coal-measures to sandstones, believed to be of Cretaceous age. In 

 No. 132 there is given an account of the " San Louis Park." an im- 

 mense elliptical basin (in which the Eio Grande del Norte takes its 

 rise), surrounded — save where penetrated by the Poncho and other 

 passes — by the lofty Sierras of the Colorado Mountains. 



The Park contains a surface-area of 9,400 square miles, at an 

 average elevation of 6,400 feet above the sea-level. Entirely around 

 the edge of the plain and uniting it with the mountain foot, runs a 

 smooth glacis, resembling a sea-beach. From this glacis rise con- 

 tinuously all round the horizon the great mountains, elevating their 

 heads above the line of perpetual snow. At 5 to 6,000 feet above the 

 plain a level line marks the cessation of vegetation, above which 

 naked granite and snow alone are seen. 



The centre of the plain is occupied by the San Louis Lake, sixty 

 miles in length, fed by nineteen confluent streams, but without any 

 outlet to its waters. Its water-surface expands over the Savannah 

 during the melting of the snows upon the Sierras, and contracts when 

 the season of evaporation returns. Seventeen lofty peaks mark the 

 serrated rim of the park, the highest of which has an elevation of 

 16,000 feet above the sea. 



The climate appears to be healthy in the extreme, and subject to 

 but little variation. 



The flanks of the mountains are clothed with dense forests of pine, 

 fir, spruce, hemlock, aspen, oak, cedar, pinon, and a variety of 

 smaller fruit-trees and shrubs, interspersed with luxuriant mountain 

 pastures of verdant and nutritious grasses. 



The mineral wealth of this region appears to be great, and only 

 needs railway transport to render it equal if not superior to any in 

 America. Already the Park is occupied by a population of 24,000 

 Mexican-American settlers, and their numbers are augmenting 

 rapidly. The details of the geology of this region will be received 

 with great interest. As many able Americans have already visited 

 and examined it, their reports may be shortly looked for. 



In No. 133, Mr. Edward Hungerford contributes a paper on 

 Evidences of Glacial Action on the Green Mountain Summits in Ver- 

 mont, whose highest elevation is 4,430 feet. 



2. In No. 11 of the American Naturalist, Dr. Jeffries Wyman 

 gives an account of some Shell-mounds or Kefuse-heaps in the State 

 of Maine. These agree in the most singular manner with the shell- 



