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The ores of Houston county belong to three classes, first, Conglomerate ores; second, Laminated ores, and third, Carbonate or clay ironstone. The last of these three classes form the most important iron ores found in the county although the conglomerates are very extensively deposited throughout the central portion of the northern portion of the county. A comparatively small deposit of laminated ore occurs in the northeastern portion of the county in the neighborhood of Robbin's Ferry on the Neches river. Full details of these ore fields will be found in the report on Houston county.

GREENSAND MARLS.

Extensive deposits of these marls occur in Cherokee county and throughout the northern portion of Houston county. They occur generally in the form of a bluish green shelly marl and brown marly sand, and are exposed in most of the deep cuttings from Crockett north-easterly to beyond Alto and northerly from this line into Anderson and Smith counties. Numerous sections of these beds have been obtained and will be given later. Such analyses as have been made of the Houston county beds show these marls to be rich in lime, and to carry from 3 to 4.57 per cent of potash, over one per cent of soda and a little over 0.1 per cent of phosphoric acid.

These marls have been used by some of the farmers of the section with good results. The yellow indurated fossiliferous marls have been used in the manufacture of lime, but although suitable for agricultural purposes they were unsuitable for building operations.

BUILDING STONES.

The most important classes of this material are the white, gray and bluish gray sandstones of the Miocene deposits and the yellow and brown altered greensand rocks belonging to the underlying Eocene.

The gray sandstones with their associated white and bluish gray sandstones have been traced and mapped from Rockland on the Neches westward as far as Riverside on the Trinity river. These sandstones form an almost continuous belt across this portion of the State, and are from six to ten miles wide at Rockland, and at the Trinity crossing cover an area of over twenty-five miles in width. They are quarried at various places along the sides of this belt for building and other purposes. The most extensive quarries are those at Rockland, where the stone is obtained for the government works at Sabine Pass, and at Riverside, where it is obtained for use at Galveston. The Rockland quarry shows a face of twenty feet and that at Riverside about the same. A quarry north of Corrigan, now abandoned, has a solid face of sixteen feet. Near Striker's Mill, on the Trinity and Sabine Railway, these rocks show a good quarrying face nearly one mile in length and from fourteen to twenty feet in thickness. Good building stone of the