the widest point is 40 miles, and its average breadth is 10 miles. It contains many islands, and its shore-line, which is extremely irregular, is deeply indented with estuaries. That part of the State which lies between the bay on the west and the State of Delaware and the ocean on the east is locally known as the Eastern Shore. The surface of this region is for the most part level, and but little raised above the sea. The peninsula between the Potomac river and the west shore of the bay constitutes another geogra phical division similar in its general features to the Eastern Shore. Its surface, however, is more undulating, and on the north-west it rises to a ledge of Primitive rocks which runs from the Potomac river at a point about 10 miles above Washington city north-east to the Susquehanna river, and separates the tide-water portion of the State from the third division. This latter region gradually rises as it extends westward until it culminates in the mountains of the great Appalachian range, which are called, in Mary land, the Blue Ridge and the Alleghanies. The principal rivers of the Eastern Shore are the Pocomoke, Nanticoke, Choptink, and Elk. These are rather estuaries than rivers, and are not navigable for any distance from their mouths. The Susquehanna flows into the bay at its head, and is navigable for a few miles. On the western shore are the Potomac, navigable for 125 miles, to Washington city, the Patuxent, the largest river which is altogether within the State, navigable for small vessels for 40 miles, and the Patapsco, on which Baltimore city is situated, navigable for 22 miles. The tide rises and falls in all these rivers. With the exception of the Youghiogheny, all the Maryland streams flow into the Chesapeake Bay. Geology and Minerals. A great diversity of geological formation is found in Maryland. The lower part of the Eastern Shore is an alluvial plain, and the numerous islands in the bay are composed of similar alluvial deposits. The northern part of the Eastern Shore, beginning at the Choptank river, is a Tertiary formation, whose strata of sands and clays overspread deposits of marl, which is of great value as a fertilizer. The peninsula on the western shore of the bay belongs to the same Tertiary formation, which, towards the north-west, gives place to a range of metamorphic rocks. This belt of rocks, which includes a strip of New Bed Sandstone, enters the State near the head of the bay, and extends south-west to the Potomac, with an average breadth of about 20 miles. The principal rocks are gneiss, talc-slates, limestone, granite, serpentine, and divers hydrated magnesian silicates. The limestone supplies a marble highly valued as a building material, and the serpentine rocks yield the valuable metallic element of chromium, which has been extensively and pro fitably worked. Oxides of iron occur in gneiss, and the Jurassic clays contain the brown hematite ores from which iron is manufactured. These ores were worked even during the colonial period, and in 1751 Maryland exported 2950 tons of pig iron to England. Bog iron ore is also found on the Eastern Shore. Beds of different kinds of clays which are used in the manufacture of bricks, porcelain, &c., are abundant, and veins of copper ore are also worked. Passing westward of the metamorphic rocks, we meet a wide belt of Silurian and Devonian formation, and the first ridge of the Appalachian range, beyond which lies the broad Hagerstown valley resting upon Trenton limestone. Numerous parallel ridges, enclosing valleys of great fertility, and .belonging to the Middle Silurian, Devonian, and Carboniferous formations, follow. This belt of lines of elevation nearly parallel with the ocean, which is a characteristic of the Appalachian chain, has, in Maryland, an average breadth of about 40 miles, and trends to the south west. The mountainous region, which extends to the western extremity of the State, but 603 with elevations rarely exceeding 2500 feet, begins at Cumberland, and here the Silurian and Devonian forma tions give place to the Carboniferous. This portion of Maryland is one of the most important bituminous coal regions in America. There are several coal-fields with horizontal seams lying near the surface, but the most con siderable is that of the George s Creek valley between Dan s Mountain on the east and Savage Mountain on the west. This narrow valley, about 20 miles long, contains the " big seam " of bituminous coal, of the extraordinary thickness of 14 feet. The Maryland coal is unequalled in the manufacture of iron and the generation of steam. The number of tons mined in 1881 was 2,261,918, and it is estimated that 550 square miles of Coal-measures remain. This Carboniferous formation also contains deposits of iron ore which are extensively worked. Climate, Soil, &c. The climate of Maryland is equable and salubrious, except in some of the lower counties on the bay, which, in summer, are subject to malarious exhalations. The mean annual temperature in the southern part of the State is 56, in the middle 54, and in the western 50. The mean temperature at Baltimore is in spring 53 8, in summer 76 0> 2, in autumn 57 - l, in winter 36 2. The mean annual temperature is 55 - 9. The mean annual barometer is 30 064 inches, and the annual rainfall 41 94 inches. The death-rate in the State is 1 81 per cent. In Baltimore city it was 19 3 4 per 1000 in 1879, and 2 4 7 in 1880. The soil of the Eastern Shore, and of the peninsula on the western shore of the bay, is composed of sand and clay, and when properly cultivated is very productive. Much attention is there bestowed upon the growth of peaches and other fruits. The land in the central part of the State, and in the valleys of the mountainous part, is of great fertility. The original forest still covers a consider able area of the western portion. There are about one hundred species of trees in the State. The deciduous oaks, hickory, chestnut, walnut, cedar, and beech trees are especially abundant. The bay and its estuaries contain inexhaustible beds of the finest oysters, yielding many thousand bushels annually. 1 There are several kinds of tortoises, the most highly esteemed of which are the Malaclemys palustris and the Ptychennys rugosa. At least eighty kinds of edible fishes abound in the waters of the State, and swimming birds are very numerous. Population, Divisions. The State is divided into twenty-three counties and the corporation of Baltimore city. The counties are Alleghany, Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil, Charles, Dorchester, Frederick, Garrett, Harford, Howard, Kent, Montgomery, Prince George s, Queen Anne, St Mary s, Somerset, Talbot, Washington, Wicomico, and Worcester. There are five cities Baltimore, the metropolis of the State, and the seventh city in the United States (popula tion in 1880, 332,313; in 1870, 267,354), Cumberland (population in 1880, 10,693), Frederick (8659), Hagers- town (6627), and Annapolis (6498), the capital of the State, and the seat of the naval academy of the United States. The body of 200 emigrants who colonized Maryland in 1634 had increased twenty-five years later to 12,000. In 1671 the population was 20,000; in 1715, 30,000; in 1748, 130,000, of whom 36,000 were negroes; in 1761, 164,007 (including 49,675 negroes); in 1775, 200,000; in 1782. 254,050 (including 83,362 negroes). The growth of population as exhibited by the decennial census returns of the United States is as follows : 1 In 1880 the amount of capital invested in the Maryland oyster business was $6,245,876 ; the number of persons employed, 24,377 ;
and the oysters taken, 10,569,012 bushels.