Notices respecting New Booh. 353 



rather delicate marine shells, in tolerable perfection. Besides the 

 strong shells of Turbo littoreus, Purpura lapillus, and Buccinum un- 

 datum, we have Mya arenaria, Tellina solidula and tenuis, Mactra 

 subtruncata ? Cardium edule*, and a shell which appears to me to 

 be Crassina scotica. The shells are most abundant along particular 

 layers in the gravel. The mass descends to a great depth, and is 

 found beneath the adjacent marsh-land, which consists of fine clay, 

 lying upon peat and trees, and is part of an extended level tract, 

 reaching from the Humber near Pattrington, almost to the sea, at 

 Sandley mere. It seems to have been, at some former period, a 

 channel for some vast volume of water ; for it winds as other valleys 

 do, and the gravel hills which bound it are abrupt on the concave 

 side, and slope gently down on the other." 



The alluvial deposits in Holderness are extensive and interest- 

 ing : 



" The lakes, which were left on the retiring of the diluvial currents, 

 appear to have been continually diminished in depth, and contracted 

 in extent, by deposits of vegetable matter, decayed shells, and sedi- 

 ment, brought into them by land-floods. In this manner a surprising 

 number of inland lakes have been extinguished in Holderness, and 

 nothing remains to denote their former existence, but the deposits 

 by which they have been filled." 



" All the lacustrine deposits containing peat, which I have inspect- 

 ed in Holderness, agree in this general fact, that the peat does not 

 rest immediately upon the diluvial formation beneath, but is sepa- 

 rated from it by at least one layer of sediment, which is seldom with- 

 out shells. The peat is very generally confined to a single layer, 

 and shells are seldom found "above it. Supposing that all the varie- 

 ties which I have witnessed in different places existed together, the 

 section would be nearly in the following general terms : 

 " 1. Clay, generally of a blue colour, and fine texture. 



2. Peat, with various roots, and plants, and in large deposits con- 



taining abundance of trees, nuts, horns of deer, bones of oxen, 

 &c. 



3. Clay, of different colours, with fresh-water lymnsea?. 



4. Peat, as above. 



5. Clay, with fresh-water cyclades, &c. and blue phosphate of iron. 



6. Shaly curled bituminous clay. 



7. Sandy coarse laminated clay, filling hollows in the diluvial for- 



mation. 



" Of these, the most constant beds appear to be No. 1, 2, and 5, 

 and, in general, these constitute the whole deposit. In different 

 places, the layers exhibit much diversity of colour, consistence, and 

 thickness. The peat varies in its thickness from five feet to less than 

 as many inches, and its constituent parts seem not the same : in a 

 few instances there are no shells in the lower clay, and when they do 



* " It must be owned the gravel shells are generally less truncate poste- 

 riorly, and less convex than the recent specimens ; but there are variations 

 in the form of Cardium edule, some individuals being more oblique than 

 others : both varieties occur in this gravel-pit." 



N. S. Vol. 9. No. 53. May 1831. 2 Z occur, 



