118 PEOCEEIXTNGS OF THE GEOLOGICAL SOCIETY. 



are none characteristic of any particular elevation above the river. 

 Bones and flint implements are said to be found throughout the 

 Amiens gravels ; but as I have never found any myself, nor seen any 

 found, I cannot speak on this point from observation ; and it does 

 not appear that these remains, any more than the shells, Tvould 

 enable us to distinguish any particular level. 



The large stones of Gres are abundant in all the quarries. I 

 made notes of the numbers and sizes of all I observed, and found 

 that they are also distributed as much in the gravel above the railway 

 as below it, and range up to 4 feet long. There are as many and 

 as large blocks of Gres in the Moutiers northern pits as in those at 

 St. Acheul. I observed one Gres at La ISTeuville partly covered by 

 loess, the rest of the stone being on gravel ; but elsewhere the Gres 

 stones were always in the gravel. 



I have mentiolied the loess being a very good brick-earth at a 

 point 120 feet above the sea in Montiers. The colour and material 

 of the loess is generally a dull brown, varying in proportions of clay 

 and sand and in the amount of angular flints contained in it through- 

 out the whole area. 1 have, however, remarked a reddish friable 

 brick-earth on the terraces fringing the Somme at Longueau, ninet}^ 

 feet above the sea. This is probably of the same character as that 

 in the similar terrace at jSTeuviUe and Montiers. This brick-earth is 

 very similar to that of the Eiver Lea ; indeed at Clapton there is a 

 well-marked terrace of brick-earth bounding the marshes, which are 

 composed of gravel. The Clapton terrace is higher than that of the 

 Somme at Amiens, and reposes on London clay, instead of chalk as 

 at Amiens. 



This low escarpment of loess is to be seen for a great many miles 

 eastward along the Somme ; and, from the angle at which it faces the 

 river, with its flat top, it so resembles a military earthwork that it 

 is often regarded as artificial. I have measured the escarpment 

 at five or six points ; and the angles vary from 20° to 40°, the 

 average being 35° (figs. 9 and 10.) 



In the Saveuse valley the angles are also various. I have often 

 remarked similar escarpments in England. I made a note of a 



Pig. 9. — Section near Cagny, in the valley of the Arve. Loess 

 Terrace just above the level of Marsh. 







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series of terraces, seven in number, one over the other, on the 

 chalk hills, on the north side of the Somme valley, about nine 

 miles from Amiens, on the Paris line ; and, indeed, in the space of 

 ten miles you may see twenty small lateral valleys opening into the 



