224 Royal Society. 



a matter of certainty, the best authenticated and the least equivocal 

 monuments of their change would abound along their coasts ; but 

 proofs are every where found that such a change is chimerical." 

 *' Yet," says Mr. Robberds, " the eastern valleys of Norfolk afford 

 throughout the whole of their extent those clear traces of the former 

 residence of the sea, which, M. De Luc here says, are not to be 

 found in any such districts; and the gradual retreat of its waters is 

 in this instance matter almost of positive historical record." 



That the valleys in question were formerly branches of a wide 

 aestuary occupied by the sea, Mr. Robberds endeavours to establish, 

 1st, hy physical proofs, and in particular by the traces of a former 

 beach composed of recent shells and loose sand, rising always to 

 the same level of about forty feet above the river, following the 

 course of these valleys and their recesses on its opposite sides, and 

 not penetrating beyond the surface of the hills. 



2ndly, By historical pj-oofs : viz. tradition ; remains of antiquity ; 

 etymology of names of villages, &c. ; and positive records. With 

 much Jearning,ingenuity aad judgement, the author has brought for- 

 ward a considerable body of evidence of this kind, strikingly corro- 

 borative of his physical proofs: among these are various Roman forts, 

 which, though now some way in-land, yet were apparently built for 

 the protection of the coasts ; the incursion of Sweyn with his fleet to 

 Norwich in 1004' ; the salines or salt works enumerated in Domes- 

 day Book as existing at various villages eight miles from the present 

 coast ; records which prove Yarmouth to have been an island in 

 1347 ; and law proceedings in 1327, which show that up to tliat 

 time ships had come up lo Norwich laden with merchandize: " all 

 these," the author states, " concur to prove that the eastern valleys 

 of Norfolk were formerly branches of a wide aestuary, and that their 

 present rivers and lakes are the remains of that large body of water 

 by which their surface was overspread, even in times compara- 

 tively recent ;" and he concludes by inferring that the change " has 

 been the result of a depression of the German Ocean itself." 



XLVIII. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



IN consequence of the decease of H.R.H. the Duke of York, this 

 Society did not resume its sittings until .Ian. 25 ; when the name 

 of Professor Jameson was ordered to be inserted in the . printed 

 lists of the Society : and a paper was read, entitled " On the expe- 

 diency of assigning specific names to all such functions of simple 

 elements as represent definite physical properties ; with the sug- 

 gestion of a new term in mechanics : illustrated by an investigation 

 of the machine moved by recoil, and also by some observations on 

 the steam-engine ; by Davies Gilbert, Esq. M.P. V.P.R.S." 



In the commencement of this paper, the author shows the utility 

 of distinguishing by separate appellations all such functions as mea- 

 sure 



