Engaged for six years in setting out and superintending the works on the Somersetshire Coal Canal, Mr. Smith found but few opportunities of making known to scientific persons, the peculiar generalizations which had taken possession of his mind. But in the execution of these works he was putting his thoughts into practice, informing the contractors what would be the nature of the ground to be cut through, what parts of the canal would require unusual care to be kept water-tight, what was the most advantageous system of work. Another singular advantage attended this engagement. The notions which up to this time he had obtained regarding the distribution of organic remains were comparatively vague. He found peculiar plants in the “clift” above the coal, particular shells in the lias and oolites, but none in the red ground, and he had combined these simple facts so far as to see that “each stratum had been successively the bed of the sea, and contained in it the mineralized monuments of the races of organic beings then in existence.” But it was the necessity of possessing an accurate knowledge of the different sorts of rock, sand, and clay, which were to be cut through on the line of the canal, which led him to examine minutely and scrupulously into the distribution of the “fossils” which he had been in the habit of collecting. The result was a proposition which he proved to be locally true, and of practical value, and which has now a world-wide application, “that each stratum contained organized fossils peculiar to itself, and might, in cases otherwise doubtful, be recognized and discriminated from others like it, but in a different part of the series, by examination of them.” In other words, he discovered that strata are to be recognized by their fossils. He now remarked also the contrast between the rounded state and mixed condition of the fossils which lay in gravel deposits and the sharply preserved specimens lying in natural associations in the strata, and thus acquired a notion of the distinction between what were afterwards named diluvial and stratified deposits.