The bulletin is preliminary in character and is offered now simply in order to meet the urgent calls for all information concerning our clays that is at present available. A more comprehensive report, in which not only the geology and distribution of our clays, but also their technological values, will be given, will follow in due course.
Data for such a bulletin are being gathered as rapidly as circumstances will permit. Among the clays upon which more field work is required are some of those associated with the coals and Conglomerate Measures of the Eastern Coalfield; those in other Lower Carboniferous regions than are included in this bulletin; those on the western rim of the Ordovician (Lower Silurian), and in parts of the Western Coalfield; while those of the Jackson\u27s Purchase region are to be studied in greater detail. It is believed that another year of field work will yield results sufficient to develop the lines along which technological work may be most profitably carried
