70 DESCRIPTION OF THE COAST. 



was at first much disposed to think this a portion of a tertiary stratum, 

 and still am altogether at a loss to explain the appearance of so enormous 

 a mass of perishable clay, having the appearance of lias at such a dis- 

 tance from the nearest cliffs of that stratum. I recommend this point 

 for further observation. The specimens of pholas crispata washed ashore 

 full of coherent sand, prove nothing whatever on this subject : such dead 

 shells are particularly liable to be filled with the matter on the bed of 

 the sea ; and the only remarkable circumstance in these specimens is 

 that the matter which they contain is unusually solidified. Excepting 

 those imperfect indications, I have never heard of a single fact which 

 would authorise a belief that tertiary strata exist in Yorkshire. 



RISE OF THE CHALK. 



No contrast can be more decided than appears between the solid, 

 regular, continuous strata which have been formed by the repeated ope- 

 rations of a primeval ocean, and the mixed and irregular aggregations 

 which mark the force and direction of subsequent diluvial currents on 

 the surface of the earth. From Bridlington pier we look southward to 

 a long line of cliffs which did not exist before the deluge, whilst north- 

 ward rise strata of chalk which, though compared to other formations, 

 they must be called of recent date, were certainly deposited and 

 hardened, and, in many places covered by several other strata long before 

 the deluge. As we proceed northward from Bridlington, the cliff, which 

 near the town was twenty-five feet high, and consisted wholly of clay 

 and pebbles, sinks to about ten feet, receives a covering of gravel upon 

 the clay, and a few layers of lacustrine sediment upon the gravel. Here 

 a small stream divides the cliff, and a chalybeate spring, issuing forth 

 from the gravel, stains the sand with an abundant ochry deposit. 

 Beyond, at a lime-kiln, the cliff is twenty feet high, and consists of 

 gravel upon pebbly clay. The gravel abounds in chalk, and contains 

 flint, quartz, porphyry, limestone, greenstone, &c. Nearly opposite the 

 village of Sowerby, the bottom of the pebbly clay is seen resting on an 

 irregular layer of chalk rubble, and the chalk itself rises from beneath, 



