$30,000. In June, 1903, a great many loads of freight, consisting of pipes for hydraulic work, were being hauled to Basin Creek over a road which follows the gravel bars of Glacier Creek nearly to its head, then crosses Banner Creek and Nome River and follows the bed of Basin Creek up to the camps.

In the bed rock of Basin Creek limestone predominates and is interbedded with some calcareous and chloritic schist. The strike is generally north and south and the dip to the east at an average angle of about 20°. These rocks certainly belong to the Nome group, and it is believed that the limestones may be correlated with the Port Clarence, and they are so represented on the geologic map. The gravels consist mainly of limestone and calcareous-schist pebbles, with a few pebbles of greenstone. An average section of the gravel where it has been exposed by mining operations is as follows:

In the pay streak over 30 per cent of the pebbles are more than 10 inches in diameter. The pay streak is about 150 feet wide, and it is said to extend along the creek for about 2 miles. The gold is bright, rough, and coarse. Nuggets worth from $1.50 to $2 are found, and many of the pieces are crystalline. The concentrates contain ilmenite, hematite, and scheelite. It is not probable that the gravels are of very high grade, for although mining began here about 1901 only a small area was worked previous to 1903. It appears that the gravels are not of sufficient value to pay wages if worked by the primitive method of stripping by hand and shoveling into sluice boxes. The limit of value can probably not be far above $6 to the cubic yard. Since 1903 mining on the creek has been done with hydraulic nozzles and elevators. The gradient of the stream bed is so great that the tailings need not be elevated more than 10 or 15 feet. With the hydraulic plants installed it is probable that the whole gravel deposit within the valley of the creek can be worked out in one or two seasons of continuous running.

Extra Dry Creek.-Extra Lry Creek flows into Nome River from the hills on the west side, about 7 miles from the sea. At its head it has a narrow canyon, but for most of its course it is trenched across the comparatively flat valley floor of Nome River. The creek gravels were being mined in 1900, when the workings were examined by Richardson." In 1903 one man was working a rocker on the creek

"Brooks, A. H., Richardson, G. B., and Collier, A. J.. Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in 1900, a special publication of the U. S. Geol. Survey, 1901, pp. 76-77.

and probably making scant wages. The whole output of the creek has probably not exceeded $20,000.

A section in the creek bed about one-half mile from its head, where the richest placers were found, showed 1 foot of muck, 1 foot of sandy clay, and 6 feet of schist and quartz gravel on mica-schist bed rock lying nearly flat. Only the lower 2 feet of gravel were worked with rockers, the water being obtained from springs. The largest nugget found was worth $13, but there were several averaging from $3 to $6, some of which were attached to pieces of quartz. In the lower part of the creek the gold is fine and little work has been done.

Dexter Creek.-Dexter Creek is a western tributary of Nome River about 7 miles from the coast. It forks about 2 miles from its mouth, the southern branch being called Left Fork and the west fork receiving the name Grass Gulch. (See sketch map, fig. 7, p. 150.) About 100 yards above the junction Grass Gulch forks again, the northern branch being called Deer Gulch. Another tributary mentioned in the economic descriptions is Grouse Gulch, which enters from the north about one-half mile below the mouth of Grass Gulch. The mines on Dexter Creek are easily reached from Nome by a wagon road which follows Dry Creek to its head and, passing over the divide, comes down Left Fork. Freight may be hauled by wagon from Nome, and in 1903 was delivered at any point on the creek for 3 to 4 cents per pound. The mines are also easily reached from either Summit or Dexter station of the Seward Peninsula Railway, to which the freight rate from Nome is at the rate of 1 cent per pound. These two stations are both on the divide between the basins of Dexter and Anvil creeks. A considerable settlement, which includes several road houses and stores, is located at the forks of Dexter Creek, the oldest establishment there being known as the "Sour Dough road house.

Through the 2 miles of its course below the principal forks the gradient of the stream is about 140 feet to the mile. Above this point, where the several branches converge, the gradient is higher. The amount of water in the creek during the dry season is less than a sluice head, but in the spring when the snow is melting and after the late summer rain there is sufficient water for sluicing in a small way. The creek valley has a V-shaped cross section and in its floor the creek flows in a shallow trench or gorge, leaving benches along its sides from 10 to 50 feet above the bed.

The bed rock of Dexter Creek consists of limestones and mica and chloritic schists of the Nome group. The strikes are in general nearly parallel with the course of the creek. Although schists predominate in the valley walls, limestone is more commonly found in the creek bed, but it is associated with some bands of schist. Rather

extensive gravel deposits have been found along the bed of the creek from its mouth to the sources of its several tributaries, and these range from 2 to 20 feet or more in thickness. Where the bed rock is limestone the gravels gradually pass into the decomposed bed rock and extend downward in crevices and fissures. Gravel deposits also occur at a number of places in benches lying parallel with the creek bed, and several of the tributary streams head in high-bench gravels covering the divides.

Dexter Creek was staked and gold on it discovered as early as 1899. In 1900 mining was in progress through the whole length of this creek and on each of its tributaries, the total output being estimated at $300,000. In many places water which passed through the sluice boxes was pumped back and used again and again. Elsewhere the gravels were washed with rockers, to which water was carried by hand or was hauled from Nome River in barrels. A criterion of the richness of the gravels lies in the fact that they were worked with rockers, using water purchased at $2.50 a barrel. In 1901 and 1902 the creek was almost abandoned, as the richest pay streak had been exhausted. With the completion of the Miocene ditch in the summer of 1902 the work on Dexter Creek was revived, and in 1903 the creek probably produced as much gold as in 1900. The water from the Miocene ditch was used over and over again as it passed from one claim to another along the creek. In general the work was done by shoveling the pay gravel into the sluice boxes, but in several places the gravel was hydraulicked. As a rule the head was only 20 or 30 feet, and canvas hose and a galvanized-iron nozzle were sufficiently strong to stand the pressure. The gradient of the creek throughout its length is such that tailings are readily disposed of. With the revival of mining along this creek a successful search for bench deposits has been carried on, and it is probable that the gravels of the creek will not be wholly worked out for several years.

At a point one-half mile from the mouth of the creek the workings in 1903 showed 6 feet of pay gravel containing many large bowlders mixed with finer sediments and clay. Most of the bowlders were of limestone and the clay is probably residual from the limestone and schist.

One-half mile farther up, on the right bank of the creek, pay gravel in the form of a bench about 150 feet long by 50 feet wide was found resting upon blocky limestone 10 feet above the present creek bed. The gold extended for some distance into crevices of the limestone, which was taken up and washed during the mining operations.

A short distance above, the pay streak in the creek bed consisted of broken limestone fragments that seem to have slid down from the

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hillside on the southern bank of the creek. This deposit is about 7 feet thick and about 30 feet wide.

On the left bank opposite this point bench gravels have been found about 75 feet above and 200 feet north of the creek bed. A pit to bed rock showed the washed gravel to be 30 feet thick. The bed rock at the bottom of this pit is reported to have a well-marked rim on the side toward Dexter Creek, indicating an old channel parallel with the present channel. Gold was found near bed rock, but the deposit had not been thoroughly prospected.

About 100 yards above the mouth of Grouse Gulch the workings on the left bank of the creek extend into a great mass of gravel, which may mark the upper end of the old channel just noted. The bed rock was here stripped for 100 feet or more, revealing a nearly level floor, beyond which it rises toward the hill. This bed rock is a decomposed schistose limestone with an irregular surface, due to the fact that some parts of it apparently disintegrated more rapidly than others. Above this bed rock lies a gravel bed which on the north side away from the creek bed has a thickness of nearly 20 feet. The section shows a layer of several feet of yellowish clay, below which there is nearly 15 feet of gravel consisting of badly sorted schist, limestone, and granite pebbles, mixed with a large amount of yellowish sandy clay.

Near the forks of Dexter Creek the gravel deposits are wider than those exposed farther downstream, but nearly all of the gravel worked in 1903 had been picked over in 1900 and 1901, when, owing to the scarcity of water, only the richest parts could be handled. The mining was done here by means of a 2-inch hydraulic nozzle under a head of 60 feet, with which the surface was first piped off almost to bed rock and carried through the sluice boxes, after which the remnant of the gravel and the loose bed rock were shoveled into the boxes by hand. The deposit worked covered an area about 60 feet wide and 250 feet long by 6 to 10 feet deep, and about half the bed rock was schist, the remainder being limestone. Gold was not found in the schist bed rock to a depth of more than a few inches, but in the fissures of the limestone the gold had penetrated to an indefinite depth. Some holes in the limestone have been found in which the goldbearing gravels are mined to a depth of 20 or 30 feet. Though the bed rock rises on the south side of the deposit, the limits of the pay gravel had not been reached. The gold here is all waterworn, the pieces are smooth, and no corners or angles remain.

About a quarter of a mile above the forks, in Grass Gulch, is one of the richest of the Dexter Creek mines. Here a pit 150 feet wide by 300 or 400 feet long, mostly on the south side of the original creek bed, had been worked out in 1903. At the upper end of this pit a face of gravel about 25 feet high was exposed at the time of Mr. Collier's visit. (See Pl. II, 4.) This gravel carried gold from a depth