Vol. 50.] 



OSSIFEROUS FISSURES NEAR IGHTHAM. 



181 



quarry was worked in platforms from the top to the bottom down- 

 wards, I had a good opportunity of noting these features, which 

 unmistakably pointed to the introduction of the debris-charged 

 waters from the side and not from above. Those cases to which 

 I particularly refer were about 30 feet from the top. 



Fig. 6 shows a view from above of one of these ' keyed blocks.' 



Fig. 6. — Plan of one of the keyed blocks, seen from above. 



In this will be seen not only the stoppage of the large bones, but 

 the direction of the waters as they deposited their sediment. It 

 will also be obvious that, since the deposition of the fissure-material 

 around these blocks, the position of the latter in regard to the 

 former has not been changed. To my mind the wedged-in state of 

 these blocks is very significant, for had they fallen from above 

 during the filling of the fissure the deposit would have formed a 

 bed for them, and so obviated the keying action ; and seeing that 

 after they fell they were covered with fissure-deposit, if the opening 

 action had been continued after a stone had become keyed, we 

 should not find a single stone so nipped to-day ; whereas there are 

 numbers in that condition all through the fissure, thereby showing 

 that the process of opening was not a continuous one, and that the 

 fissures have been stationary since their first filling. 



IV. The Fossil Plants and In vertebra ta found in the Fissure. 



In working down the face of the quarry for the first time I kept 

 all the fossils from the various levels separate, expecting to find a 

 Cave-like succession ; but on comparing them with my notes taken 

 while work was progressing I could see nothing to warrant a sepa- 

 ration either in the state of preservation of the specimens or in the 

 occurrence of species — a conclusion simultaneously and indepen- 

 dently arrived at by Mr. E. T. Newton. In some places certain 

 species were naturally more plentiful than others : sometimes frog- 

 bones were more numerous than all the rest of the bones put 

 together, at others they were in the minority. I have seeD a large 

 wall of the deposit cleared on one side for a considerable distance, 

 and throughout its whole extent it was perfectly solid ; it is certain 

 that water could not have transferred the fossils from one part of 



