J. L. LOBLEY — CRETACEOUS ROCKS OF ENGLAND. if 



posing whole counties, consist almost altogether of the shells of 

 animals so minute that thousands would be required to form a 

 cubic inch. Yet such is the fact, and not only so, but these humble 

 workers are still at work, and have been working ever since the 

 summit of the highest down in England was a portion of the bed 

 of a deep sea. 



"We are indebted, however, for this knowledge to researches of 

 but a few years ago. Science produces inventions, and gives to 

 the useful arts most nourishing food. The arts again give 

 rise to research and exploration, which yield to Science its only 

 suitable food — facts. Science has given us the Electric Telegraph, 

 and the Electric Telegraph has required for its due development 

 the exploration of the bed of the ocean. The exploration of the 

 bed of the Atlantic Ocean gave to Science the great fact that there 

 is now forming a deposit precisely analogous to our English Chalk, 

 — that, in short, at the bottom of the Atlantic is a mass of white mud 



Fig. 3. — Foramiuifera from the Fig. 4. — Foraraiuifera from the 



Chalk, magnified 50 diameters. Atlantic ooze, magnified 25 dia.* 



or ooze, of which 95 per cent, consists of shells of the same genus, 

 nay, even of the same species of animal which formed the Chalk in 

 the Cretaceous epoch. This mud or ooze is none other, therefore, 

 than Chalk in process of formation, and we are, by the soundings 

 for the Atlantic Telegraph Cable, shown the origin of our English, 

 our Hertfordshire Chalk. The name of the prevailing species of 

 the modem deposits is Glohigerina huUoides, which closely resembles 

 the most common form in the Chalk, but many others occur, such 

 as those shown in the diagrams on the walls.f 



The recent investigations of the Challenger expedition have 

 revealed other facts of a deeply interesting character. The white 

 calcareous ooze, composed of the shells of Foramiuifera, though 

 covei-ing an immense area at the bottom of the Atlantic, does not 

 extend the whole length of the Atlantic canal, which at its northern 

 and southern extremities rests on a bed composed of siliceous 

 matter, the accumulated cases of another Class, the Polycistina, 



* The Foraminifera in these figures are copied from illustrations in Professor 

 Geikie's ' Primer of Geology.' 

 t Some of the forms here alluded to are represented in Figs. 3 and 4. 



