J 826.] which appear on the Yorkshire Coast. 341 



In describing the deposits which occupy, and give the charac- 

 ter to, these successive regions, I shall endeavour to avoid all 

 details which are not absolutely necessary to my present purpose ; 

 as my only object is to ascertain the relations of certain pheno- 

 mena which have already been elaborately and faithfully 

 described in a work to which I have before referred. On this 

 account, I shall notice the successive formations in the order in 

 which they are described in the " Geological Survey of the 

 Yorkshire Coast," beginning with the most superficial, and end- 

 ing with the lowest strata of the district. 



Sect. 2.— Strata of Holderiiess. 



Nearly the whole of this first region is composed of diluvial 

 detritus. Some account was given of the deposit in a paper 

 (published in the ^«//a/s of Philosophy for July, 1825), in which 

 I endeavoured to ascertain its connexion with other similar 

 deposits in the neighbouring parts of England. Any further 

 notice of it in this place is unnecessary. 



In so extensive a district, composed exclusively of materials 

 which are superior to the chalk, some traces of m7/a/y beds 

 might be expected to appear in the sections on the coast. But 

 no traces of them are seen in any part of the chffs south of Brid- 

 lington. In some places, however, a very impure variety of coal 

 is occasionally cast up on the beach, which may, perhaps, be 

 derived from some inferior carbonaceous beds similar to those 

 which abound in many parts of the plastic clay formation.* 



By the degradation of the coast immediately on the north side 

 of Bridlington Quay, a bed of green-sand, extending through a 

 distance of eight or ten yards, was laid bare at the l)ase of the 

 clifF.t It contained many incoherent bivalve shells, and very 

 much resembled some of the beds which are found in the higher 

 part of the sand-pits of Woolwich. I considered it an undoubted 

 proof of, at least, a partial existence oi tertiary beds in that part 

 of England. With the crag of Suffolk, it ought not, I think, to 

 be confounded. 



Mr. Smith, in his Geological Map of Yorkshire, mentions the 

 occurrence oi crag shells ar.d sand in the interior of Holderness. 

 I have not seen any of the deposits to which he refers, and am, 

 therefore, unable to determine whether they are to be classed 

 with the Suffolk crag, or with the shell-beds of the plastic clay 

 formation. Mr. Smith's system of arrangement unfortunately 

 does not enable us to make" the separation. 



• These varieties of impure coal must not be confounded with specimens of pure pit 

 coal, which are occasionally found on the beach, having been wrecked or scattered on tlie 



t I have been informed that this bed of green sand is now concealed by some works 

 constructed, in the year 18'^ I, ii>i the purpose of preventing the encroachments of the 

 ica. 



