346 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



icebergs through various channels, and the thrusting forwards masses 

 of frozen gravel along and upon the coasts, the general drifting cur- 

 rent coming from E.N.E. At a subsequent period, and during 

 convulsion and general disturbance (possibly not unconnected with 

 the latest upheaval of the insular mountain chain*), enormous waves 

 appear to have swept the island from the N.E., or N.E. by E., 

 depositing erratics on the highest points, and filling up the valleys 

 with an accumulation of diluvium. The drift gravel may be con- 

 sidered as merely the subsequent spreading out, with greater uni- 

 formity, of the same material over the then sea-bottom ; and it is 

 not unreasonable to conclude also, that there had been through the 

 whole of this period a filling up of the area of the Irish Sea, so that 

 on its subsequent elevation the present Isle of Man was connected 

 v/ith the surrounding countries. The preservation of the tertiary 

 beds of this island from the continued destruction, which enabled 

 the sea to recover so large a portion of its ancient area, is evidently 

 due to the configuration and position of the island ; whilst the for- 

 mation of the valleys of denudation, and the hollows in which the 

 ancient alluvia repose, seem to indicate that there was at first a 

 gradual rise terminating in a sudden elevation of this area. But 

 further facts have been adduced pointing to its subsequent sub- 

 mergence, followed again by a second partial emergence, and this 

 latter movement has left the Isle of Man as a nucleus of palaeozoic 

 rocks, fringed with tertiary marine and freshwater formations be- 

 longing to the most recent geological period. 



Appendix. — List of Fossils from the Pleistocene Marine Formation 

 of the Ish of Man, collected by the Rev, J. G» Cumming and named 

 hy Prof E. Forbes. 



Pectunculus pilosus. 

 Cyprina islandica. 

 Astarte gairensis ? 

 Artemis exoleta ? (fragments). 

 Astarte damnoniensis. 



pisiformis ? f 



Venus casina. 



Pullustra decussata?' 



Nucula rostrata (oblonga of authors). 



minuta. 



• Cardium edule? 



Isevigatum. 



Tellina solidula. 

 Dentalium entalis. 



* It may be useful to observe, that the direction of the great fault lifting South 

 Barrule, and producing cracks at right angles, coincides exactly with the line of 

 those disturbances and cracks in the neighbourhood of Eoualdsway and Coshna- 

 hawin, the occurrence of which after the deposition of some portion of the boulder 

 formation, I have before shown as not altogether improbable, 



t Named by Mr. G. B. Sowerby. 



