REMARKS ON THE DILUVIUM. 105 



It is difficult to assign the native repositories of the beautiful agates, 

 heliotropes, and jaspers, which are found on the shores of Holderness, 

 Speeton, and Scarborough, after the wintry storms have caused the fall 

 of some portions of the diluvial cliffs. They are probably all productions 

 of trap rocks, possibly derived from the hill of Kinnoul and other amyg- 

 daloidal basalts of Scotland. The question as to the nature of the 

 beautiful dendrizations in moss agate remains unsettled ; for Dr. M'Cul- 

 loch's ingenious experiments leave doubts on their vegetable origin, 

 which botanical investigation has not removed. Jet, another interesting 

 product of this diluvium, may be traced to the neighbourhood of Lyth, 

 where considerable masses of it have been obtained from the cliffs of 

 alum shale. It also occurs in other parts of the lias series, rather fre- 

 quently in the lower shale near Skinningrave, generally in connexion 

 with fossil woodj of which it forms the external layers. Seams of it 

 also divide sandstone blocks in Hawsker bottoms. Magnetic sand 

 (oxydulated titaniferous iron) occurs in great plenty on the shore where 

 diluvial cliffs are exposed to rapid waste, or their disintegrated materials 

 are retained in some sheltered bay. It is particukrly abundant at Scar- 

 borough and near Hilston in Holderness. 



Teeth and tusks of the mammoth are almost the only remains of qua- 

 drupeds, which I remember to have been found in the diluvium of this 

 coast, and these have been obtained at several points near Hornsea, 

 Bridlington, Scarborough, and Robin Hood's Bay. Remains of the 

 same kind, with or without bones and teeth of oxen, deer, and horses, 

 have been found in gravel pits at Brandsburton, Hessle, and in the 

 vale of York. Upon the whole, therefore, the diluvium in the eastern 

 part of Yorkshire possesses the general characters of that deposit, and 

 agrees, in a particular manner, with the accumulations of the same a3ra 

 which have been so long known and so well examined in the eastern part 

 of Norfolk. 



