Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/722

Rh 680 form, sometimes 80 feet in length, and of aquatic habits. The Tertiary deposits, including the boulder clay, prevail chiefly along the seaward districts, from Long Island, above New York, to the peninsula of Florida, and around the shores of the Mexican Gulf, and likewise on the Pacific shore from Lower California to Vancouver Island, also in some detached instances, as in Nebraska, in the midst of the interior plain. The newer Pliocene is met with in the southern part of Maine, and on the shores of Lake Cham- plain. The drift formation lies mostly north of 40 lati tude. Alluvial deposits are of great amount from the large rivers and lakes, especially in the delta of the Missis sippi, which has an area of 13,600 square miles, and must, by Sir Charles Lyell s reckoning, have taken 67,000 years for its composition, at the rate of the bringing down of solid matter by that mighty river. iuerals. The mineral products of North America are of unequalled richness and variety. Gold is abundant, to a proverb, in California, and likewise in Nevada and Montana. It is also found in British Columbia, Mexico, Central America, and Canada, and sparingly in Virginia and South Caro lina. Silver is obtained from Mexico in larger quantities than from any other country; it is supplied also by Cali fornia and by Honduras, and a vein of this metal is worked in Newfoundland. Great masses of almost pure copper are found in the Huronian rock strata, the north and east shores of Lake Superior being the richest of copper-mining regions; while New York State and Indiana possess a share of the same metal, and it is found among the wes tern mountains in different countries from British Columbia to the isthmus. The iron ores of Pennsylvania, and those of Canada, including New Brunswick, are of the greatest importance; the former are rendered more available by their occurring close to the beds of bituminous coal, giving materials for the manufacturing industry of Pittsburg; while anthracite coal is obtained from the eastern districts of Pennsylvania. It is estimated that one-third of the total area of this State is occupied by coal-fields, which can scarcely be exhausted. Lead is found in Wisconsin, Illinois, and Missouri, in New York State, in Canada, in California, and in Central America, as well as quicksilver ; white zinc is got from Arkansas and New Jersey ; both Canada and Mexico produce tin. lleverting to the subject of coal, as having an intimate economic connection with all metallic wealth, it should be observed that the united area of all the coal-fields in the United States is estimated at 190,000 square miles, exceeding twentyfold those of Europe. The chief of these coal-fields are, first, the Appalachian, extending from the Susquehanna, in Pennsylvania, to the Tuscaloosa, in Alabama, along the west side of the Alle- ghany Mountains ; the area of this coal-field is 70,000 square miles, and its greatest thickness 2500 feet ; secondly, the coal-field of Michigan, about the centre of that State; thirdly, the extensive coal-field between the Ohio and the Mississippi, across the States of Indiana and Illinois ; lastly, the Iowa and Missouri coal-field, which occupies a large space in the very centre of the continent. Coal is found also in Nova Scotia, in British Columbia, and Van couver Island, and wherever the Upper Palaeozoic strata prevail in the geological structure. But in the vast extent of British American territory north-west of Lake Superior, around Lake Winnipeg and up the Saskatchewan river, even as far as the Peace river, in latitude 56 N., it may be expected that manufacturing as well as agricultural prosperity will result from the use of immense stores of natural wealth existing in the soil of that long-neglected land, which is now proved to have a climate not more severe than the inhabited provinces of Canada. The iron and copper, more especially of the Canadian Dominion, will employ and enrich, in all probability, at some Suture [N. AMERICA. period, a nation that may become greater in material resources than the most powerful kingdoms of Europe. In view of these prospects from the working of the useful metals, by the aid of that most useful product of the earth which supplies heat and mechanical force to the service of human industry, we may regard the Californian gold-fields as a matter of secondary importance. They have indeed been surpassed by the productiveness of those in Australia and New Zealand. Nine-tenths of North America lying under the tempe rate zone, the climate follows a different law from what is observed in the southern peninsula, and presents more strik ing contrasts with that of the best known parts of the Old World. The long narrow region now denominated Central Central America, which connects the two great divisions of the con- and Nor tineut, stretching from Panama to Tehuantepec, has in A &quot; en :i general a very humid atmosphere; but, for a tropical coun try, it must be only moderately hot, as every part of it is within a small distance of the sea. At Vera Paz the rains fall during nine months of the year. Mexico is hot, moist, and unhealthy on the low coasts ; but two-thirds of its area, comprising all the populous districts, consist of table-land, from 5000 to 9000 feet in height. In consequence of this singular configuration of its surface, Mexico, though chiefly within the torrid zone, enjoys a temperate and equable cli mate. The mean heat at the capital, which is 7400 feet above the sea, is 62|, and the difference between the warmest and coldest months, which exceeds 30 at London, is here only about 12; but the atmosphere is deficient in moisture, and the country suffers from drought. Beyond the parallel of 24* N. the western shores are hot and arid. In the extensive region lying between the parallels of 30 and 50 N., which comprehends three-fourths of the useful soil of North America, we have three well-marked varieties of climate, that of the east coast, the west coast, and the basin of the Mississippi. On the east coast, from Georgia to Lower Canada, the mean temperature of the year is lower than in Europe by 9 at the latitude of 40, and by 12J at the latitude of 50, according to Humboldt s calculation. In the next place, the range of the thermo meter is much greater than in Europe, the summer being much hotter and the winter much colder. At Quebec the temperature of the warmest month exceeds that of the coldest by no less than 60| of Fahr.; while at Paris, which is nearly under the same latitude, the difference is only 31. In the third place, the climate undergoes a more rapid change in America as we proceed from south to north, a degree of latitude in the middle of the temperate zone pro ducing a decrease of annual temperature of 1 13 Fahr. in Europe, and of 1 57 Fahr. in America. The comparison is greatly to the disadvantage of America when made in this form; but when the east coasts of the two continents are compared, the case is altered ; the Old World is found to have no superiority over the New, for Pekin has still colder winters and warmer summers than Philadelphia, which is under the same latitude. It is the west coast of the new continent which ought to exhibit the climate of Europe ; and from the observations made, we have reason to believe that it is quite as mild and equable. At the mouth of Columbia river, in latitude 46 J- N., it appears that the mean heat of the warmest month was about 62 Fahr., of the coldest about 36, and of the whole year 51. Now the place is under the same latitude with Quebec, where the snow lies five months, and the mean temperature during the three winter months is 18 below the freezing point. This single circumstance marks emphatically the contrast in the climate of the east and west coasts of North America. But the mouth of Columbia river is also under the same parallel with Nantes at the mouth of the Loire ; and we have, therefore, good grounds to conclude that the west