J. L. LOBLEY CRETACEOUS ROCKS OF ENGLAND. 13 



in Surrey, and the Tottemhoe Stone of Buckinghamshire and 

 Hertfordshire. 



The Lower Chalk is generally described as the Chalk without 

 flints, though these curious siliceous nodules do occasionally occur 

 in the Lower Chalk, and are occasionally wanting in beds of the 

 Upper Chalk. This division is less brilliantly white than the 

 Upper Chalk, and contains fossils not found in the higher beds. 

 Between the Lower Chalk and the Upper Chalk a hard bed is 

 found at several localities, and has been called by Mr. Whitaker 

 the Chalk Eock. 



The Upper Chalk or the Chalk with flints, is characterized by its 

 softness, its brilliant whiteness, by its numerous bands of flints, and 

 by its fossils, which are numerous and interesting. This is the 

 Watford Chalk, though it is probable that the Chalk of Norfolk is a 

 higher bed of the same division. The fossils of the Chalk confirm 

 the teaching of the Foraminiferal character of the rock itself, and 

 proclaim the formation to be purely marine. Sponges are numerous, 

 many being inclosed in the flint nodules. Sea-urchins (Echinoderms) 

 — Micraster, Ananchytes, Galerites, Marswpites, abound ; and bivalve 

 shells — Terehratula, lilujnchonella, Spondylus, Pecten, Inoceramus, 

 etc., are common. The discoidal chambered shells called Ammonites, 

 allied to the recent Nautilus, sometimes attain very large dimensions, 

 and are especially interesting since none have since lived in the 

 seas of the earth so far as we know ; while vertebrate animals are 

 represented by the fishes which are frequently found both in the 

 Lower and in the Upper divisions. On the Continent of Europe, 

 Cretaceous beds higher than the Chalk, and containing reptilian 

 remains, are found; but these deposits, called the Maestricht beds, are 

 wanting in England, and nothing but a band of green-coated flints, 

 telling of beds dissolved away, separates the Chalk from the 

 Tertiary beds above. 



The Cretaceous rocks of England, it will be seen, possess an 

 interest to the student of ]S"ature of no mean order. Various in 

 lithological character, possessing rich stores of organic remains 

 which tell a wondrous story, contributing striking features to the 

 landscape, affecting greatly the botany and zoology of extensive 

 districts, and all easily accessible from this neighbourhood, they 

 strongly invite your attention and study. The Field Meetings of 

 this Society will give you opportunities of obtaining a personal 

 acquaintance with the rocks and the phenomena they exhibit, and 

 of prosecuting the study of geological science in the most agreeable 

 and at the same time most advantageous manner. The knowledge 

 of the Cretaceous rocks will induce the investigation of other 

 groups of strata, older and newer, and you will, I trust, be led on 

 step by step in the great field of geological investigation until you 

 become possessed of a large amount of geological knowledge. 



