436 Mev. Mr. Vernon on the Strata [June, 



above-mentioned clay, were the leading objects of our re- 

 search. 



The most westerly range of rising ground shov/n by the map 

 (Plate XXXVIII) in this tract is at North and South Cliff, and 

 here, if any where, we conceived the lias was to be traced. Our 

 route was, therefore, directed across the strata from Holme on 

 Spalding Moor, by N. Cliff to Sancton. At Holme we found 

 the summit of the hill to consist of gravel, but the red marie 

 appeared about a mile to the SE with gypsum imbedded in it ; 

 the gypsum is worked for plaster, and being divided into two 

 qualities, the one white and pure, the other coloured with grey 

 marie, is sold at the rate of a guinea and twelve shilHngs a ton 

 The red marie shows itself for some distance on the road from 

 Selby to Cliff, and is then covered by a sandy alluvium which 

 overspreads the country as far as the Cliff hills. 



On arriving at North Cliff, we found at once a little to the 

 northward of the village, the tirst object of our search, and at an 

 opening made for the purpose of burning bricks, discovered the 

 lias well characterised, and containing the distinctive fossils,^ 

 of which specimens are before the Society. Mr. Phillips made 

 a sketch of the section which it here presents, the only one to 

 be seen along the whole range. We subsequently traced the 

 course of this stratum southward, with some difficulty from the 

 circumstance of the stone not being worked ; it appeared, how- 

 ever, at the surface near South Clitij and we. detected it again at 

 Hotham, at Everthorpe, and at the western end of the village of 

 South Cave ; at these places we found its peculiar pentacrinites 

 and gryphites in heaps of blue clay and septaria taken out of 

 wells, one of which had been sunk twelve years ago, but the 

 materials had remained undisturbed. The stone extracted from 

 the well at Everthorpe had a peculiar hollow oolitic structure. 

 We are disposed to assign also to the lias the clay of which 

 bricks are made at Brough, and again on the road from Sancton 

 to Market Weighton. On a hill near the latter place, we found 

 it marked by gryphites in a brick yard ; and at a point near 

 Goodmanhani, on the road to South Dalton, where I had 

 formerly noticed the red chalk marie, we found under the red 

 chalk a rock distinguished by the same hollow oolitic grains 

 with which we had been struck at Everthorpe, certainly belong- 

 ing to the same stratum. Beyond this point its outcrop has 

 been observed by Mr. Smith all along the western side of the 

 Wolds by Pocklington and Seppington to Craike, and the lias 

 may, therefore, be considered as having now been traced in an 

 uninterrupted course from the Humber to Whitby. 



Our examination of the next range of hills to the eastward 

 commenced at Sancton, where the oolite tirst appears passing 



» 



Plagiostoma gigantea, Auimonites, 



Plagiostoma tusticum, Pentacrmus caput Medus*. 



