406 Mr. J. Phillips's Geological Observations made 



and finally unite above and exclude the clay from the surface. 

 (See Plate II.) 



The red and white clay in the deepest parts of a " horse " 

 contains not a single pebble such as lie in the diluvium, but 

 abounds in fragments seemingly very little worn, of the lower 

 shelly bed of the limestone. At the surface, indeed, where 

 the red clay and diluvium come in contact, the pebbles of the 

 latter deposit are more or less mixed with the former; but 

 still the appearances are such that no person can doubt the 

 conclusion, that the diluvium was laid on the surface long after 

 the red clay had been introduced into the chasm of the lime- 

 stone. 



Observing that the spaces which are filled by these red 

 horses are not necessarily connected with the surface, but are 

 often subterranean, and descend quite to the base of the lime- 

 stone, while the long straight joints which were open to the 

 surface are filled by other materials, — I am induced to believe 

 that the red clay was forced into its present situation from be- 

 neath. In appearance it is very similar to the stratum which 

 lies beneath the limestone : from all that can be observed, it 

 is probably connected with it ; and it is remarkable that the 

 angular fragments which it contains belong chiefly to the lower 

 shelly bed of the rock. In what manner such an upward 

 flow of the red clay could be occasioned, is not easy to con- 

 jecture ; nor will my silence on this subject be condemned by 

 those who have learned from experience what difficulties at- 

 tend the theory of ordinary dykes and mineral veins. 



No. 5. — The red marl formation is seen reposing upon the 

 limestone of Knottingley at the third bridge over the new 

 canal through that village. It presents the usual appearance 

 of red and blueish layers in frequent alternations, but contains, 

 I believe, no gypsum. 



No. c 2. — Diluvium. 



Over all the strata which have been mentioned, sand and 

 gravel are extensively spread ; but seldom accumulated in such 

 vast quantities as in the lower country, which lies to the east 

 and north-east. The surface of the upper limestone is in ge- 

 neral regular, and the gravel upon it of nearly uniform thick- 

 ness. In almost every quarry at Knottingley and Brotherton the 

 fixed rock is covered by a variable layer of its own substance 

 in the form of rubble, which sometimes is so slightly water- 

 worn and so unmixed with other materials, that it appears to 

 have been merely loosened and disturbed, but not transported. 

 Above, we commonly find sand, with or without pebbles of 

 sandstone and mountain limestone, resembling the varying 

 beach thrown up by the sea? and then, in the Brotherton 



quarries, 



