324 GEOLOGICAL SURVEY OF TEE TERRITORIES. 



through the sandstone ridge about a mile and a half from Ealston Creek, 

 and is known as Leiden's mine, from the name of the late owner, who 

 with two other men lost their lives by entering the mine last September, 

 when the air was foul in consequence of its having been left nnworked. 

 It continued for some time inaccessible, and smoke was issuing from 

 the entrance, when the writer visited the place five days after the occur- 

 rence mentioned above. The locality is of interest as showing the con- 

 tinuity of the coal. The formation is easily traced northward from this 

 point over a broad and highly-elevated open plateau, hj the strata of 

 sandstone projecting in vertical layers above the surface ; and the coal 

 can, without doubt, be found anywhere against the western edge of the 

 strata, or in the depressions below the general level now occupied by 

 ponds. The lands, however, are not likely to be soon occupied, the soil 

 being filled and covered with small boulders from the mountains ; still, 

 by irrigation, a considerable portion of them may be made productive; 

 and the fact that several ditches are already made across these tracts to 

 the lower and better lands to the east shows that water is available 

 even at their high levels. But the coal is more profitably obtained in 

 the valleys of the creeks than in the elevated divides. 



In the next valley crossed by the belt, that of Coal Creek, some seven 

 miles from Ralston Creek, another opening is met with under the western 

 edge of the same sandstone ridge. The mine, however, is not now 

 worked, the owners finding it more convenient to develop their other 

 property near South Boulder Creek, two or three miles over the next 

 divide to the north. 



Marshall's. — The mines in the valley of South Boulder Creek, known 

 as Marshall's, are among the earliest worked in Colorado. They were 

 in operation in 1863, and have continued without interruption to fur- 

 nish coal to Denver twenty-two miles distant, and to the neighboring 

 settlements. The locality is a little to the south of the creek, in the 

 hills bordering a small branch about two miles below the foot of the 

 mountains. As many as four beds of coal have here been opened, two 

 of which may, however, prove to be the same. One of them — the 

 highest in the series — is found just under the summit of the divide, dip- 

 ping gently toward the southeast. It is known as the Dabney bed — is 

 said to be nine feet thick, and when worked, furnished coal of a superior 

 quality, especially for blacksmiths' use. At a lower level, and also 

 lower in the formation, is found the main bed, which is worked to the 

 thickness of ten feet, through the w r hole of which the coal is remarkably 

 clean and free from slate and other impurities. It contains very little 

 pyrites in their disks and some resin in small particles. In the mine 

 the freshly-exposed face presents a beautifully brilliant appearance, and 

 the coal is so found that a cubic block of it, said to weigh over three 

 tons, was taken out for exhibition at the fair in Denver. It is used very 

 generally by the blacksmiths, who have overcome the difficulty they 

 formerly experienced in not being able to get up a welding heat with it. 

 The mine is worked by two parallel headings, or levels, driven in from the 

 north side of the hill, and rising a little up the slope of the bed. These 

 extend about six hundred feet in, and rooms are worked on each side, 

 but chiefly up the slope. In the other direction the bed passes under 

 a meadow, wdien the coal will have to be worked and drained by means 

 of vertical shafts. It is now mined for $1 25 per ton beside cost of 

 props and keeping the track, &c, in good condition. 



A third bed of coal three feet thick is found across the meadow just 

 spoken of, in the hill to the east, not half a mile from the main bed. It 

 dips eastwardly into the hill, and has been followed down the slope sixty 





