The most important branch of production, according to its value, was that of coal. After this came the various materials used in the manufacture of brick and ceramics. The building stone, although limited to a few varieties of limestone and sandstone, was of great importance, as was also some stone and gravel used for road material, railroad ballast, concrete, and flux for iron reduction. The exhibit of coal consisted of a series of large blocks intended to show the character and thickness of the veins; the largest block, weighing 15 tons, is the largest single piece ever hoisted from a mine. There are 11 of these blocks from different mines, ranging from the largest down to one block of 1 ton. In clay products the importance of the industry could only be shown by statistics, as common brick, which is made all over the State in such a uniform character, are so well known that exhibits are not necessary. Neither the geology nor topography offer many opportunities for the development of stone quarries, but such stone as is extensively used was displayed. The limestones of the Silurian series are the principal sources of supply, the quarries about Joliet being among the largest in the United States. The limestone is generally used in the form of rubble or rock-faced ashler. The exhibit at the United States Fish Commission Building was in the large aquarium situated in the southeast corner of the building and the two smaller aquaria immediately adjoining on the right and left. In the large aquarium the commissioners decided to show the commercial fishes of the State--that is, such fishes as were commonly used for shipping and found in greatest abundance, namely, the carp, buffalo, the coarser catfishes, and dogfish. The dogfish in the last few years has become a very important factor in the food supply, having been previously thrown away as worthless, but is now extensively used by a class of people in the larger cities and sold alive under the name of grass bass. In this aquarium has been carried, for a period of seven months, perhaps the largest amount in weight ever carried in an aquarium for that length of time with so small a percentage of loss. In the smaller aquaria were shown the game fish of the State, a list of which comprises the black bass, crappie, sunfishes, yellow perch, white perch, warmouth bass, and the two varieties of striped bass. These aquaria have attracted a great deal of attention, particularly among those who were interested in the subject of fish propagation and distribution, and gave people a better idea of what Illinois produced than could have been obtained by any other method.