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THE FARMER'S MAGAZINE. 



civil engineer, such as the construction of machi- 

 nery, and the determining of the motive powers 

 of water. Canals were then as much the order 

 of the day, as railroads have been in our time. 



The formation of canals rendered necessary new 

 ])rojects for surmounting difficulties arising from 

 irregularities of level, such as locks, caissons, and 

 inclined planes. To these new objects Smith de- 

 voted his attention, and seized every opportunity 

 of acquiring information, and in qualifying himself 

 for the new career which was opening on him. 

 " This," says his nephew, and biographer Profes- 

 sor Phillips, " was a tide in his affairs, which, had 

 he followed the middle current, without stopping 

 to examine the banks, would have led him on to 

 fortune ; and even under the great disadvantage 

 of being suljject to a strong deflecting current, his 

 career was not unprosperous, and he joined with 

 tolerable compactness the decisions of an engineer 

 to the inquiries of a geologist." 



In 1793, while engaged in levelling for a canal, 

 he had opportunity of proving the truth of a specu- 

 lation which had entered his mind as a conjecture 

 only during the course of his previous operations, 

 namely, that the strata above the coal, which had 

 been originally deposited horizontally, rested upon 

 one another in an inclined position " like the slices 

 of bread and butter in a plate," to use his own 

 homely simile. The levellings which he executed 

 in two parallel valleys confirmed these views ; for 

 in each of the levelled hnes 'the strata of red marl 

 lias and oolites came down in an eastern direction, 

 and sunk below the level, yielding place to the 

 next in succession. 



He knew at the same time that the position of 

 the strata of coal in Somersetshire was not gene- 

 rally conformable to the red marl and other strata 

 above the coal series. He was aware also that the 

 faults which divide all the coal strata undei'ground 

 are not found in general to affect the strata which 

 rest on the coal measures. 



Smith had soon an opportunity of confirming 

 these general views respecting the succession of 

 the strata, by more extended observation. 



On the completion of the Canal Bill in 1794, the 

 committee of management deputed two of their 

 members to accompany Smith on a tour of inspec- 

 tion respecting canals. This tour, which occupied 

 between one and two months, and likewise em- 

 braced the observation of collieries, extended over 

 900 miles, and reaching Newcastle by one route, and 

 returning by Shropshire, Wales, and Bath, gave 

 him an opportunity of testing his preconceived 

 opinions respecting the order in which the strata 

 succeeded one another. 



During this tour he found his general views jus- 

 tified, and the strata in the vicinity of Bath pro- 



longed in the same general order of succession to the 

 eastward. From the top of York Minster here- 

 cognised by their contours the chalk strata of the 

 Wolds ; and from this information, and from their 

 relative position, and their ranges on the surface of 

 the lias and the red marl, occasionally seen on the 

 road, he was enabled to lay down on his map, with 

 a considerable approximation to accuracy, the pro- 

 longation of the chalk of Wiltshire and the oolites 

 of Somersetshire, through the eastern parts of 

 Yorkshire. 



Smith was engaged for six years in superintend- 

 ing the works of the Somersetshire Coal Canal, 

 during which time his geological discoveries re- 

 mained comparatively unknown to the public, 

 though he had frequent opportunities of rendering 

 them available in practice, by informing the con- 

 tractors what would be the nature of the ground to 

 be cut through, what parts of the canal would re- 

 quire most care in order to keep them watertight, 

 and what would be the most advantageous system 

 of work. It was during this period that the neces- 

 sity for close observation of the different kinds of 

 rock, sand, and clay, which were to be cut through 

 on the line of canal, led him to the conclusion that 

 certain fossils distinguish certain parts of the series. 

 He had previously obtained a glimpse of this 

 generalization, from the plants of the coal measures 

 and their absence from the red marl ; but these ex- 

 tensive cuttings through more fossiliferous beds, 

 confirmed, extended, and generalized them. They 

 were embodied by him in the following general 

 conclusions : That each stratum contains organic 

 fossils peculiar to itself, by which, in cases other- 

 wise doubtful, it may be recognised and distin- 

 guished from beds otherwise like it, but in a dif- 

 ferent part of the series. 



The observations which the works of the 

 canal rendered necessary, led him also to a 

 distinction between stratified deposits and those 

 superficial accumulations containing far-trans- 

 ported materials, to which the name of "dilu- 

 vium " was given by him (not by Buckland, as we 

 stated in a former article respecting the geological 

 evidence of the Deluge), and which have since re- 

 ceived the names of " northern-drift " and " erratic 

 tertiaries." This change of names involves no 

 change in the nature and distribution of these de- 

 posits ; it is only that more extended observations 

 have brought to light more extended knowledge 

 respecting facts connected with the mode of theirfor- 

 mation, and more accurate information respecting 

 their distribution. Their marine origin has since 

 been proved — not merely conjectured — by the ma- 

 rine shells of existing species which have been found 

 extensively distributed through these deposits at 

 various elevations, extending to near 1,400 feet. 



