coal seams sometimes reaches 150 feet; now in 150 feet there are 1,800 inches or 3,600 half inches. At the present rate of growth in vegetation, therefore, it would take 3,600 centuries or, 360,000 years, to accumulate this amount. Startling as these facts may appear, we need not go over the ground of again asserting and proving that they do not militate against Holy Writ; the believer in revelation, who peruses them, may rest somewhat satisfied with the fact that some of the best geologists have been, and are, the firmest believers in its truths; whilst in works which have been written with much care by able and learned men, he may meet with arguments and expositions sufficient to answer every question, and to dispel every fear.

The stratified rocks, however, are not, as is often supposed, arranged in a promiscuous manner, but are found in certain relations to each other. These relations are never reversed, but are so regular that the rocks may be arranged in classes and formations as truthfully as though we had seen them deposited. It is true a certain class of rocks may be missing, but they are never found out of their places, that is, if we were to arrange them downwards, beginning from the surface with A, and go on through the letters of the alphabet; we should never find A below B, nor D above C; C might be absent, and thus B rest upon D, but still the order of consecutiveness is followed. This fact is one of the most important to miners, because from this it is evident that, if we know the nature and name of the surface rock, we also know something of those below. This fact is among many others which geology has been the means of elucidating.

The following table of the stratified rocks is taken from Lyell's Manual of Geology.

Many of the names given to these rocks are purely arbitrary, and in many instances, arose from local pecularities. Of them all, perhaps, the Tertiary formation, with its sub-divisions, is the most neatly arranged, it being now accepted after the modification of Sir Charles Lyell. Most of the terms employed in connection with the cretaceous formation are arbitrary. The Maestricht beds take their name from the place where they are developed; those of the green sand from their colour, although this is not a continual feature. The different sub-divisions of the Oolite are named after the localities where they were first studied, and where they may

now be seen. The Triassic, is so called from its three sub-divisions; the bunter sandstein, the muschelkalk, and the keuper of most geologists. The Permian formation was so called by Sir Roderick Murchison, from it being discovered by him largely developed in the Russian province of Perm. The carboniferous formation is, of course, so called from its coal bearing properties; the mountain limestone is often given to the lower portion of it, from its often forming vast portions of mountain chains. The term "carboniferous limestone," however, is now retained as being preferable. The Devonian is so named from its being first observed and studied in Devonshire, and its commoner term of "old red sandstone," from its often prevailing colour. The Silurian is named after the ancient British tribe of Silures, from its being developed in their country, and lastly, the Cambrian formation is so named, because it is extensively developed in Wales. Most of these names given to the rocks, therefore, it may be seen are of arbitrary origin. They were given to them in the earlier history of the science, and have been retained ever since, from motives of convenience.

The mineralogical structure and appearance of a rock, or class of rocks, is not a necessary, or even a common accompaniment. Many of the names of colour which are attached to the rocks, were given from the appearance they presented in the first observations. Thus, red sandstone is not a necessary accompaniment of either of the formations bearing that name, there being vast beds of light coloured sandstones and conglomerates interstratified with them; neither is the red colour confined to them, as this may be seen in beds of the carboniferous formation, and, according to Sir Charles Lyell, also in the tertiary deposits. The carboniferous limestone, which in England is partly of a crystalline structure, in Russia passes into a kind of chalk. The oolitic appearance, which was at first given to the deposits of that name, from the roe-like structure of the limestones, is now known to be common to the rocks of the carboniferous period, and more recent formations. The chalk and green sand rocks, also possess appearances much in common with other rocks, having brown sandstones and beds of clay interstratified with them; so that the mineralogical structure or colour of any rock cannot be depended upon as a criterion; it may, under some circumstances, assist in filling up data for comparison, but will never prove an infallible guide alone.

What then are the means employed in arriving at the knowledge

of different rocks, or how may we detect rocks of one formation from those of another? This question is an important one, inasmuch as its truthful answer will prove of valuable practical results : there is, however, only one answer to it, viz. :-by their organic remains alone. Simple as this answer may appear, it is nevertheless a positive fact that the different rocks may at once be known from their imbedded fossils. It is upon this fact that the classification of geology is founded. Hence a wide field opens out to us, which is of the greatest importance. Transport a geologist anywhere, and place him, hammer in hand, before a class of rocks he never saw or heard of before, and he will tell you from the fossils he may chip out, the relative age and position of the rocks in question. The different rocks yield their characteristic fossils as truly as different trees bear their peculiar kind of fruit. A botanist would never expect from any freak of nature to find figs growing upon thistles, or grapes upon the bramble: just as soon would a geologist think of finding trilobites in the oolitic formation, or ammonites in the Silurian.

Thus, from a knowledge of organic remains alone, mining need not be a matter of speculation, but is reduced to the laws of a practical science. The surface rocks may at once be detected, and thus the greatest obstacle removed. Had this knowledge been possessed by many an intelligent speculator, it would have saved to him both time and money. Perhaps a few anecdotes may show the importance of this knowledge, and impress it more surely upon the mind. Sir John Herschel, speaking of the practical importance to be attached to this class of information, states that a few years ago an attempt was made to establish a colliery at Bexhill, in Sussex. The appearance of the seams, and sheets of fossil wood and wood coal, with others similar to those met with in the coal yielding districts of the North of England, led to the sinking of a shaft and the erection of machinery on a scale of vast expense, and not less than £80,000 is said to have been laid out on this project, which any geologist would have pronounced futile, for the appearances presented were in the Hastings sand, one of the Wealden beds, thousands of feet in vertical thickness above the carboniferous formation.* Some years ago a boring was prosecuted for coal in the lower beds of the carboniferous limestone at Castletown, in the

Sir John Herschel's "Discourse on Study of Natural Philosophy."

Isle of Man. This limestone is intercalated with black shales, supposed to be of volcanic origin, and containing the usual fossils of the limestone; perhaps the appearance of the shales deceived the borers; however, the boring was continued into the beds of the old red sandstone beneath; and it was not until some thousands of pounds had been expended that the search was given up, and even at the present time the belief is confidently indulged in by many of the inhabitants that had the miners but gone deeper, they would most assuredly have discovered coal. A fact of a similar kind is narrated by the late Hugh Miller in his " Old Red Sandstone," others are mentioned by Murchison in his "Silurian System." Richardson also mentions a case that came under his own observation within a mile of Northampton. The geological

site of the locality is about the middle of the oolitic formation, which, to a geologist, would at once be indicative of the fruitlessness of the search after coal. He at once denounced the enterprise as fruitless, but his remonstrances were disregarded. The enterprise seems to have originated in the supposed resemblance of a bed of clay, discovered in sinking a well, to those which generally underlie the coal, and on this appearance a joint-stock company was formed, steam-engines erected, and shafts sunk; the result may easily be apprehended. The works, after being extensively prosecuted, were finally closed after an expenditure of £20,000.

Mr. Jukes, the director of the geological survey of Ireland, writes on this subject as follows:-"Within my own experience I have known vast sums of money absolutely thrown away, which the slightest acquaintance with palaeontology would have saved. I have known, even in the rich coal district of South Staffordshire, shafts continued down below the coal measures deep into the Silurian shales, with crowds of fossils brought up at every bucket, and the sinker still expecting to find coal where no coal had ever yet been found. I have known deep and expensive shafts sunk in black shales and slates in the lower rocks, far below the coal measures, where a pit might be sunk to the centre of the earth without ever meeting with coal; nor are these fruitless enterprises a thing of the past, they are still going on in spite of the silent warnings of the fossils in the rocks around, and in spite of the loudly expressed warnings of the geologist who understands them, but who is supposed to be a vain theorist, and not to know so much as the Practical Man.'" In another place the same geologist