452 REPORT — 1895. 



have twisted in the least. The ' extractor ' was then lowered to break off 

 and draw up the core. A length of 18 inches only was brought to the 

 surface, and this was in three pieces. Upon each of these pieces the 

 vertical marks of the cutters were found, and the lines were seen to be so 

 cut as to show that when they were made, the parts of the core were yet 

 in their relative positions. The force, moreover, which had to be applied 

 to break the core before it coidd be raised, as well as the unrubbed condi- 

 tion of the lowest of its pieces, sufficed to prove that all the parts were 

 in situ at the time at which they were marked. 



A length of core still remaining fixed at bottom, the wax was sent 

 down again. This time, the bottom of the marking tube lodged for an 

 instant during its descent on the top of a lining tube some 800 feet down, 

 but at once swung off, giving a shock to the rods that caused the radial 

 arm to strike against the staging and turn slightly round on the rod to 

 which it was clamped. The lowering was then completed, the impression 

 taken, and the tube brought up again. It was found to have turned 

 through an ansjle of 3° 11' from the direction in which it stood before 

 being lowered. Taking into consideration the fact that when no acci- 

 dental disturbance occurred no variation was observable, and that the 

 direction of the displacement corresponded with what would be caused by 

 the blow on the arm, it was clearly justifiable to assume that the angular 

 movement observed was entirely attributable to the shifting of the de- 

 scending pointer at the time of the lodgment on the side of the hole. By 

 taking the bearing of the marked diameter as it returned to the surface 

 instead of as it commenced to go down, the error due to the misfortune 

 was corrected. When the core was brought up there was no diflSculty in 

 fitting the wax cast to the rock and transferring the diametrical line. 



The two experiments gave identical results, and from this it was com- 

 puted that the direction of the dip of the Devonian Rock at Turnford at 

 a depth of 994 feet below the surface, and 1-4 feet below the top of the 

 stratum, is about 17° west of true south. The angle of dip is about 25° 

 from the horizon, as shown by numerous layers of fossils. 



It thus appears that at both places these ancient rocks dip in directions 

 lying between south and sou'-sou'-west, and by placing on a geological map 

 of the south-eastern portion of England lines to show the ascertained bear- 

 ings (fig. 13), it is at once seen that the greatest inclinations of the strata are, 

 roughly speaking, at right angles to the directions of the chief axes of the 

 Weald. Soon after the completion of the borings a statement seems to 

 have been made, without due authority, that the general direction of the dip 

 had been found to be towards the south-east, and, unfortunately, the mis- 

 take does not seem to have been publicly refuted until now. It is time that 

 this misconception were removed, for geologists who are interested in the 

 search for coal in the eastern counties evidently attach considerable impor- 

 tance to a correct knowledge of the disposition of these Palaeozoic rocks. 



Mathematical accuracy could not be expected in operations of this 

 nature, but I believe the bearings of the lines of dip at both places, as 

 herein given, may be looked upon as practically correct, the maximum pos- 

 sible error being not more than one degree east or west. Before the various 

 appliances were perfected there occurred numerous failures to which no 

 reference has been made, but the details given tend to show that no trouble 

 was spared to attain satisfactory results. More than a month was entirely 

 devoted to this ascertainment of the direction of the dip at each place, and 

 in some cases several days were spent in a single operation of lowering and 



