“Besides the ferns, then growing to a great size, there were other plants whose modern representatives are uniformly small; but as the resemblance in this case is simply one of general form, and the great majority of other trees seem to possess no living type to which they can be referred, it is by no means impossible that these also may be completely lost. One example of them is seen in a plant, fragments of which are extremely common in the coal measures, and which has been called _calamite_.[62] The remains of calamites consist of jointed fragments, which were originally cylindrical, but are now almost always crushed and flattened. They resemble very closely in general appearance the common jointed reed, growing in marshes, and called _equisetum_, or mare’s tail; but instead of being confined to a small size, they would seem to have formed trees, having a stem more than a foot in diameter, and jointed branches and leaves of similar gigantic proportions. They were evidently soft and succulent, and very easily crushed. They seem to have grown in great multitudes near the place where the coal is now accumulated; and though often broken, they seldom bear marks of having being transported from a distance.”[63] The fossils of the carboniferous system here figured we found not long since in the neighbourhood of Stockport. [Illustration: CALAMITES. ] [Illustration: CALAMITE. ] [Illustration: STIGMARIA FICOIDES. ] This chapter on the carboniferous system must not be further lengthened. We do not aspire to teach the science of geology; we aim only to impart such a taste for it as shall lead the reader to consult our master works on this subject, and if we succeed in this humble but useful aim, our purpose will be fully answered. Only in reference to the economic uses of coal, we will quote the following, copied, we believe, from the “Athenæum” some time since, but unfortunately copied without reference to its original; a lesson for common-place-book keepers. The writer in speaking of coal-gas says: “The consumption of gas is enormous. The following statistics give us an insight into the extent which this branch of industry has attained. In England 6,000,000 tons of coals are annually employed for the manufacture of gas, and from 12,000,000 to 15,000,000 pounds sterling expended in its production. In London alone 500,000 tons of coals are annually used, producing 4,500,000,000 cubic feet of gas, and 500,000 chaldrons of coke; of the latter, 125,000 chaldrons are consumed in manufacturing the gas, and the remainder sold for fuel. Upwards of half-a-million houses in London burn gas, and the length of the main arteries for conveying it is 1,600 miles. The capital employed in the metropolis is 4,000,000_l._ The manufacture of coal-gas for the purpose of illumination affords one of the most striking instances of the triumphs of science when enlisted in the divine cause of civilization. Looking at it as a whole, and regarding the ingenuity