the land of that time. The sea coast then extended from the region of the present sound northward and southward. Along the coast were extensive swamps, and the streams coming from out the Cascades emptied into the sea through great estuaries. About these estuaries existed a luxuriant growth of vegetation, and here grew the forests from which were made the great fields of coal with which our state is so well supplied. These fields of coal, several in number, extending from the neighborhood of Whatcom to the vicinity of Castle Rock, were all formed independently of each other, and were never connected, although they have many striking resemblances. The coastal region of that period alternately rose and fell through a long lapse of time. When it rose, the vegetation flourished in the swamps and about the estuaries, and when it fell the accumulated vegetable matter was covered by sediments of sand and clay, and ultimately converted into coal. The repeated oscillation of level, along with the growth and burial of vegetable matter, produced in this way in the course of time a great series of seams of coal. In some of our coal fields over one hundred distinct veins of coal have been discovered. The great majority of these are thin, and will never be of any great value economically. There are seams of coal eight or ten feet in thickness, however, which are of course easily worked, and are of great value. When originally formed, the coal beds were all practically horizontal, but some time after they were made they were subjected to mountain-building forces and were thrown into great folds. So it happens that we find our coal beds dipping at angles varying from a few degrees to entirely perpendicular. The Roslyn coal field, lying upon the eastern slope of the Cascades, belongs to the same period as the western field, but had a somewhat different history, in that the coal plants grew upon the shores of a great lake of that region, instead of along the shore of the sea.

Miocene Period.

The completion of the western parts of the State from the old sea coast mentioned above to the present Pacific border took place in what is known as Middle Tertiary, or the Miocene period. It is possible that in the Olympic mountains, however, there may be metamorphic and sedimentary rocks of a much earlier age, possibly as old as any represented in the Cascades.

It is also possible that the great volcanic activity of the Olympics may have been synchronous with that of the Cascades, but these matters can be determined only when the Olympic mountains are more fully explored. Lying at the base of the Olympics, and extending throughout the southeastern part of the State, sandstones, conglomerates, shales, and other common sedimentary rocks occur, and from their abundant fossils they are easily recognized as of Miocene Tertiary age. Rarely do these rocks occur in their original horizontal position, as they, too, have been folded and crumpled, and considerably eroded.

Columbia Lava Plain.

There now remains but one section of the State to be described geologically, and that is the large area known as the Columbia lava plain. About the Miocene Tertiary period, as far as we know, this great region was a comparatively low plain, with occasional high hills, especially upon the eastern borders, near the present Idaho line. It is to be presumed that the rocks. comprising this plain were composed largely of the same material as those of the Cascades, lying to the northward and westward. Within the floor of this old plain great fissures were formed at different places, and through these masses of molten rock came from the depths below and flowed out in great sheets. This molten rock, upon cooling, was of a black color and of a variety known as basalt. The rock was in such a highly molten condition that from each fissure the lava flowed very many miles before cooling and coming to a standstill. After the first great outpouring there came a time of quiescence, the lava cooled upon the surface, and a soil was formed which supported a considerable vegetation. In time, however, there came other flows, the vegetation was largely destroyed, the only remnants remaining being layers of petrified wood and charcoal, now found interbedded with the layers of lava. In this fashion, with alternating periods of activity and times of quiet, the great lava plains of the Columbia were formed. The depth of the lava varies from two thousand to four thousand feet. In a few cases the higher hills of the ancient plains, such as Steptoe, Butte, and others, were never covered by the basaltic sea, and now appear virtually as islands. Of such great depth is the lava that only the larger, deeper streams, such as the Snake, have eroded through the lava

and uncovered the older rocks which lie below. It may be assumed that the surface of the lava at the conclusion of the last flow was approximately level, and that it extended in a monotonous plain from the foothills of the Cascades to the mountains of Idaho, but here, as elsewhere in the state, mountain-making forces have been actively at work, with the result that the comparatively level lava plain is now crossed by many high ridges, and even mountains. In the western part of the plain may be noticed the Badger mountains of the Great Bend country, the Rattle Snake hills and several east-west ridges which lie to the westward of the Columbia, and greater than all, the Blue mountains, a great dome-shaped mass of lava rising fully seven thousand feet above the sea. These mountains are comparatively even-topped, but at the same time they are much dissected by streams, and abound in deep canyons.

In this brief outline of the State's geological history, mention can not be made of many of the episodes, such, for instance, as the oscillations of the coast, whereby the lands adjoining have been alternately flooded and laid bare; or the large lakes which were formed upon parts of the Columbia lava, and which existed long enough for their floors to be covered with sediment of great thickness.

One event of the State's later history, however, must be mentioned, and that is the formation of great glaciers upon the mountains of the State, and their movements southward as far as the line of the geological map designated as the southern limit of glaciation. Glaciation in Washington was no doubt closely connected in time and cause with the general glaciation of the northern part of North America. It occurred in the first part of the present age, known as the Quaternary. Attempts have frequently been made to estimate the time which has elapsed since the glacial period, the estimates varying from ten thousand to one hundred thousand years. In glacial time, upon the summits of the Cascades, the Olympics, and the coastal mountains of British Columbia, glaciers of enormous size were formed. In the region about Puget Sound these giants met, and here we find the glacial sediments, consisting of boulders, gravel, sand and clay, of a thickness unknown elsewhere. So great in quantity is the material which the glaciers transported from the neighboring mountains, that only at points widely apart does the

bedrock about Puget Sound appear at all. The glacial sediments not only constitute the floor and shore cliffs of the Sound, but over large areas about the Sound they form the local gravel plains known as "prairies."

MINERAL RESOURCES OF WASHINGTON.

Although the knowledge of our mineral resources has come to us slowly, yet we feel certain that in them lies a giant of tremendous possibilities, which will one day make Washington one of the most prosperous states of the Union. In an article of the brevity of this, it is possible to speak only of the best known of our natural resources, and of those only in a very general way. Localities can receive but scant mention, and the writer can hardly touch upon, or even hint, concerning the progress of development or of the work of transforming the crude minerals into useful products.

In the distribution of gold and silver we find that these minerals are practically limited to the older rocks of the State. It is therefore very improbable that prospecting in the rocks of a later age will ever bring satisfactory returns to the prospector. The veins of gold and silver among these older rocks occur most commonly in the granite or the diorite, but they are also found in the gneisses, slates, and in other metamorphic rocks as well. As a rule the sulphide ores predominate, and so the gold and silver occur with galena, iron pyrite, chalco-pyrite, zinc blend, arseno-pyrite, and other similar minerals. Free milling ore is the exception, although there are a few districts, such as Slate Creek and Swauk, where such ore is of great promise. The discovery lately of tellurides of gold in the Mount Baker and other districts has given rise to the hope that we may have developments of a Cripple Creek order in some of our mines.

One marked characteristic of the gold and silver deposits in this State lies in the great extent of the ore bodies and in the almost inexhaustible quantities of the ore. It is true that the ore is usually of a low grade, although ores of the very highest value are occasionally found. Altogether the precious metal deposits are of such a nature that while their development must necessarily be slow, yet there is no question but that the quality and quantity of the ore justify and will lead to the erection of large mining plants which will yield to their owners a good revenue for years to come.

The world-wide interest which has lately developed in copper has naturally made that metal sought after in Washington. Within a brief space of time several districts of Washington— at Index, along the Carbon river, and elsewhere - have come into prominence because of their copper minerals. In its geological occurrence the copper minerals have a distribution similar to that of the gold and silver. The copper occurs in veins and is found in the granite more commonly than in the other rocks. The copper minerals are for the most part sulphides, like those of Butte, Montana. In a few instances native copper is found, as are also the oxides and carbonates. In the most prominent copper localities of Washington the bodies of ore, while of low grade, are unusually large and give every indication of being of very great value.

Many other minerals, such as lead, arsenic, zinc, molybdenum, etc., are also found, either alone or in connection with the precious metals. These in time will come to have a value of their own. In some instances they will be mined independently of any other mineral; in others they will be saved as byproducts during the process of extracting the principal metals from the ores.

Up to the present time the mineral veins most worked have been those carrying coal. For many years coal has been mined in Washington, and the recent stimulus in all industrial matters has led to a greatly increased output from the coal mines of the State. Our coal fields are several in number, and unlike those of Pennsylvania, seem never to have been connected, but were of distinct origin. Each seems to have been formed independently of the others, although in the character of coal and in age they closely correspond. The coal fields are characterized in general by a large number of veins, and in many instances these veins are of unusual thickness. The coal basins are covered to great depth by glacial materials and very heavy forests, which fact accounts for the lack of knowledge concerning their extent. It is believed, however, that careful study will show the coal fields to be greater in extent than is generally supposed. Without doubt there lies stored within them a vast wealth.

As the State increases in population the demand for building stones of different varieties will correspondingly increase, and the quarrying of our stone become one of the great industries of