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XII. 



NOTES ON LITHOTHAMNION MET WITH IN DEEP CUT- 

 TINGS AT THE MOUTH OF THE RIVER LIFFEY. 

 By J. P. O'REILLY, C.E., Professor of Mining and Mineralogy, 

 Royal College of Science, Dublin. 



[Eead April 24, 1893.] 



DiTRiNG the course of the years 1871-72, the deepening of the extremity 

 of the south quay-wall was being carried out under the direction of 

 Dr. Stoney, C.E., and by the contractor, Mr. W. J. Doherty, C.E., and 

 foundations were being sought at a depth of 24 feet 6 inches below the 

 Datum-line of the Port of Dublin. Passing by the works on the 5th 

 August, 1871, I saw on the quay what appeared to be a heap of shelly 



a, Line of o Datum of port, d, Drift, c, Blue clay, d, Bed of hazel-nuts, 

 leaves, and vegetable remains without shells, e, Speckled clay, with roots and 

 trunks of trees. /", Bed of shells. ^, Gravel. 



sand, so relatively clean that the forms of the shells could be dis- 

 tinctly recognized at once, but presenting the peculiarity that the 



