NATURAL ASPECTS OF HULL AND DISTRICT. igi 



mounds, causing the many pleasant undulations variously 

 named "holmes," "rises," "barffs," and "broughs." Very 

 interesting to the geologist are the contents of these gravels, 

 consisting as they do of pebbles, ice-scratched, far-travelled 

 stones, and bones and teeth of animals like the wild ox, 

 reindeer, and the extinct mammoth. The Boulder Clay 

 accumulations are the earliest of the Post Pliocene geological 

 formation. The reassortment of the mud derived from the 

 glacial drift has made the many patches of alluvium near the 

 rivers and smaller streams, which are included in the later 

 Quaternary System. 



The Wolds for the most part belong to the Cretaceous 

 System, the youngest of the Secondary (Mesozoic) Systems, 

 and immediately underlie the Boulder Clay, there being no 

 certainty that the Tertiary epoch is represented in our district 

 as it is copiously in East Anglia. The Cretaceous System 

 includes the Neocomian (locally Speeton Clay) and the lower, 

 middle, and upper chalk formations, all of which are well 

 exposed at no great distance from Hull. The Neocomian is 

 of exceptional interest, being a better exposure near Speeton 

 than any where else in the world. The curious may be 

 referred to the interesting work entitled, " Argiles de Speeton," 

 by Mr. G. W. Lamplugh, F.R.S., and M. Pavlow, of 

 Moscow. Of the fossil animal contents of the chalk forma- 

 tions there are innumerable opportunities for collection and 

 study in chalk pit, quarry, and cliff. Foraminifera like those 

 of the Atlantic ooze, sponges, mollusc shells, sea-urchins and 

 their allies, scales of fishes and sharks' teeth, all in greatest 

 variety and fair abundance will reward the interested seeker 

 after nature-knowledge, and tell unmistakably the history of 

 the earth's vicissitudes. Of the economic value of the common 

 white rock called " chalk," there is abundant evidence in the 

 whiting mills and lime kilns that are found in many places on 

 the Wolds. Emerging from below the chalk strata, and 

 forming low hills and terraces round the western escarpment 

 are rocks of the Jurassic System — Oolite and Liassic. These 

 are readily distinguished from the chalk and sand rocks by 

 their yellow and more fertile soil, as, for example, near Brough 

 and North and South Cave. The Newbald and South Cave 

 Oolite quarries furnish the only building stone, but that not 

 of the best, that is obtainable in the East Riding. 



Still westward and we are on the " Levels," an alluvial 

 region with a great depth generally of sand and gravel, which 

 bears more of the heathy character than anywhere else in the 

 neighbourhood. The "Levels" are underlaid by Triassic 



