Page:Popular Science Monthly Volume 1.djvu/649

Rh Yet it is the opinion of explorers, that here, as elsewhere, the deposits are in minor basins, united perhaps in places, but, as a rule, constituting separate beds, over a vast area of depression. Hayden says there is good reason to suppose that this area "extended northward far into Canada, and southward with the Cordilleras;" a supposition that, if true, would give an extent of coal-lands, in this section of the continent, much greater even than that just mentioned.

The Rocky-Mountain deposits are regarded as belonging to a much later geological age than those of Pennsylvania or of Rhode Island. While the latter belong to the Carboniferous age, the former are found chiefly in the upper Cretaceous or Chalk period, or in the so-called Tertiary; which brings the period of the Western coals nearly down to the latest geological ages.

The value of the Rocky-Mountain coals is unquestioned. From various analyses, it appears, that their volatile constituents reach about 38 per cent., while the amount of fixed carbon is estimated at about 50 per cent. Pennsylvania anthracite is much richer in fixed carbon, but the coals of Iowa, as well as some Scotch and English varieties, are considerably poorer in this respect. But, apart from their fixed value as sources of heat, the coals of this region derive an additional importance that can hardly be over-estimated, from their geographical position. In a country without timber, and far removed from other sources of fuel, they supply the first requirement for the development of its resources, and have already become the object of an extensive and thriving industry.

Lessons from a Brick.—An Austrian savant has discovered, by means of a microscope, in a brick taken from the pyramid of Dashour, many interesting particulars connected with the life of the ancient Egyptians. The brick itself is made of mud of the Nile, chopped straw, and sand, thus confirming what the Bible and Herodotus had handed down to us as the Egyptian method of brick-making. Besides these materials, the microscope has brought other things to light—the débris of river-shells, of fish, and of insects, seeds of wild and cultivated flowers, corn and barley, the field-pea, and the common flax, cultivated probably both for food and textile purposes, and the radish, with many others known to science. There were also manufactured products, such as fragments of tiles and pottery, and even small pieces of string made of flax and sheep's wool.

Zoology of the Galapagos.—A correspondent of the Tribune, accompanying the Hassler expedition, gives an interesting account of the animals observed in the Galapagos Islands. He says:

Over 50 different kinds of fishes were obtained, and of these over three-fourths are peculiar to the Galapagos. Of the Galapos, from which the islands are named, and in which they once so richly abounded, we only got a few specimens, and those very small compared with those of olden time. They have been so eagerly hunted for their flesh that they have been driven from the more accessible places, and stand a good chance of being altogether exterminated. Their brethren in the sea, the tortuga or sea-turtle, we saw in abundance, and got some very fine specimens. There are, as is tolerably well known, two other reptiles for which this archipelago is famous—two lizards, of a genus not found elsewhere, and very peculiar in their habits. The Spaniards called them iguanas, from their resemblance to that reptile in the West Indies and Central America. But they differ so much from their American cousin that they ought to have a name of their own, and if the scientific Amblyrhynchus looks too formidable, let us translate it and call the creature a Bluntnose. On Charles Island we found abundance of the crested Bluntnose climbing with great agility over the rocks near Black Beach. The creature is about 80 inches long, nearly black, the old males having a deep-red hue on the sides. It swims with great ease by its flat tail, and uses its long fingers and long nails for scrambling on the rocks, holding them, while swimming, close to the body. There is not a trace of web-footedness about them, and they make no use of the feet in swimming. They live on sea-weeds from the rocks in deep water, and their expression is mild and herbivorous, with a little clear, innocent eye. I was prepared for something hideous, and was agreeably disappointed. In another respect our experience differed from Darwin's, for we sometimes had no difficulty in frightening them into the water, and they came fearlessly swimming about the Hassler as she lay in Tagus Cove. These crested Bluntnoses we found upon all the islands. The slightly-crested Bluntnose we found only on Albemarle and Indefatigable.