114 



REPORT — 1873. 



Similar phenomena are observaUe along the western shores of the British coast. 

 Along the shores, bays, and headlands of Argjdeshire and Ayrshire we find the 

 fringe of shelly gravel, the old coast clift", with caves and sea-stacks now high and 

 dry, at an elevation nearly corresponding with that of the caves, shelly sands, &c. 

 of the Antrim coast. Southward, towards the shores of the Solway Firth, the 

 elevation decreases, and this decrease continues till the evidences of a raised beach 

 almost disappear towards the estuarj^ of the Mersey. 



The identity, therefore, of the phenomena on both shores is evident, and is a 

 matter of some interest in the physical geology of these islands. 



12'i'Vtttiun of the Coast since the human period. — Another feature of identity of the 

 beaches on both sides of the channel is the occurrence of works of human art im- 

 bedded in undisturbed strata along with marine shells. Mr. Geikie mentions that 

 thirty canoes have been dug out of the 2o-feet terrace along the estuary of the 

 Clyde. Along the Irish coast the abundance of worked Hints testify, as Mr. Dii 

 Noj'er has shown, to the presence of man along these shores when they were to a 

 greater degree than at present under water. These flints have also been observed 

 in the gravels of the coast of Dowushire, as well as in spots in the interior, and at a 

 considerable elevation above the sea, imbedded in the soil. 



Shells of the liaised Beach. — The shells which occur in this gravel are generally 

 blanched and fragmentar};, but are all of species at present existing in the adjoin- 

 ing sea. The following arc the names of some at three ditt'erent localities, in 

 the identification of which the author has been assisted by Mr. W. II. Baily, F.G-.S. 



Along the shores of Belfast Lough the raised gTavel-beach rests on a blue clay 

 of estuarine origin, containing a large number of genera and species of shells, of 

 which Mr. J. Grainger has named eighty species*, to which Mr. S. A. Stewart 

 has added others f. Some of these species have disappeared from the Lough, 

 and others are exceedingly rare. 'S^^hen this estuarine mud was deposited the 

 waters must have extended considerably beyond their liniits, even at the time of 

 the formation of the " 20-feet " gravel-beach. The author suggested that this 

 estuarine inud may represent the earlier period of submergence — marked in the 

 west of Scotland by the " 40-feet " water-line, of which traces have been noticed 

 by Scottish geologists J. 



» Trans. Erit. Assoc. 1852, p. 4.3. 



t List of Fossils of the Estuarine Clays of Down and Antrim, 1871. 



J Ai'chibald Gcikic, ' Scenery and Geology of Scotland.' 



